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7mm Cartridge Guide

Posted By admin On October 4, 2010 @ 2:30 am In Cartridge Guides | No Comments


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7mm Accuracy Cartridges
7mm WSM, 300WSM, Remington S.A. Ultra Mag, Rem SAUM, .284 Win
7mm-08 Rem | .284 Winchester | 7mm WSM | 7mm SAUM

Long recognized as a superb choice for hunters, the 7mm (.284) bore size is now attracting great interest among long-range match shooters as well. The 7mm occupies the “sweet spot” between 6.5mm and 30 caliber–with an optimal balance between bullet weight and BC. It’s hard to beat 7mm ballistics with either a 6.5mm or a reasonably-sized 30, and the 7mm will give longer barrel life than a 6.5 mm with less recoil than a 30-caliber (of equal BC). To match the ballistics of a 7mm 180gr VLD with a 30-caliber bullet, you must move up dramatically in bullet weight–to a 210gr or larger bullet. To drive the heavier 30-caliber bullet at similar velocities, you’ll need more powder. More powder and a much heavier bullet weight means more recoil (and attendant fatigue) for the 30-caliber shooter. The combination of great ballistics with manageable recoil has made the 7mm cartridge a favorite among long-range prone and benchrest shooters. The chamberings of choice are the .284 Winchester, 7mm Winchester Short Magnum (7mm WSM), and 7mm Remington Short Action Ultra-Magnum (7mm SAUM). For silhouette shooters and hunters, the 7mm-08 is a top choice (but not the only choice).

New Interest in the .284 Winchester
For many years, the “original” .284 Winchester lived in the shadow of the smaller 6.5-284. That is all changing. Today there is great interest in the .284 Win. Charles Ballard used a ‘straight .284′ recently to win the 2008 F-Class Nationals convincingly. With its short, stubby case, and rebated rim, the .284 Winchester is a very efficient cartridge. With the latest high-BC 7mm bullets, the original .284 Winchester is proving tough competition for its 6.5-284 offspring. And now, with the introduction of Reloder 17, the .284 Win is capable of driving 180gr VLDs at nearly 3000 fps, a speed that once demanded a short magnum (or bigger) case.

7mm Short Magnum Options
Speaking of short magnums… improvements in components and propellants have spurred new interest in the 7mm short mags. Among the short action magnums, most interest has focused on the 7mm WSM (and 300 WSM necked down to 7mm) until very recently. However, Norma has started producing 300 Rem SAUM brass, and that has sparked new interest in the 7mm SAUM. Read our report below and you’ll see why the 7mm SAUM may just be a better choice than the WSM for 175-185gr bullets. Are there downsides to the fashionable Short Magnums? Yes. First, many shooters stepping up from a .308 Win or 6.5-284 find that a 7mm WSM pushing 180s at 3000+ fps beats them up during an extended match. The extra recoil takes its toll. The other “Achilles heel” of the Short Mags is barrel life. Make no mistake about it… hot-loaded Short Mags wear out barrels quickly. It’s not unusual for a 7mm WSM to “go south” after just 700-900 rounds, though some barrels will last longer.

We thank all the talented shooters who provided research and commentary for this 7mm Cartridge Guide. Major contributors include: Charles Ballard, Vince Bottomley, James Hardy, Bryan Litz, Steven Ikeda, German Salazar, Jerry Tierney, and Robert Whitley.

Berger Bullets J4 Jackets

Factory Reloading Data
7mm-08
55.0 grains Capacity
.284 Winchester
66.0 grains Capacity
7mm WSM
81.0 grains Capacity
7mm SAUM
73.6 grains Capacity
Accurate Arms
Alliant Powder
Hodgdon & IMR
Sierra Bullets
Vihtavuori
Accurate Arms
Alliant Powder
Hodgdon & IMR
Sierra Bullets
Accurate Arms
Alliant Powder
Hodgdon & IMR
Sierra Bullets
Vihtavuori
Accurate Arms
Alliant Powder
Hodgdon & IMR
WARNING: ALWAYS start 10% below stated max loads and work up. Pressures can vary dramatically from one barrel to another. Seating depths have a huge effect on case pressures–moving the bullet just .015″ one way or another can push a “safe” load into the danger zone. Powder lot variances can be extreme–you may have to adjust a full grain or more. Whenever you buy new powder, even the same brand, start 10% low. NEVER assume pressures will be safe if you change lots or ANY component. Case web growth is probably the most reliable indicator of over-charge. By the time you’re getting stiff bolt lift or ejector marks with fresh brass you’ve exceeded proper pressure levels. Ambient temperatures can alter pressures considerably. Don’t assume cold weather loads are safe in summer. As you approach max loads, reduce the load increments. Just 0.2 grains can make a difference.

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7mm Shooters Enjoy a Wide Selection of Great Bullets

One of the best reasons to shoot a 7mm cartridge is the huge selection of truly outstanding projectiles, in weights from 100 to 180+ grains. The line-up below shows but a small fraction of the excellent 7mm projectiles available today. As the 7mm has been a favored hunting, military, and target caliber for well over a century, bullet-makers have had plenty of time to perfect their art. For game hunters, the choice of great bullet designs in 7mm (.284 caliber) is rivaled only by the wealth of 30-caliber bullets, and the 7mms enjoy a ballistic advantage, grain for grain, over the larger-diameter 30s. All the major bullet makers offer outstanding hunting bullets in the 130-160 grain weight range: Barnes 140gr TSX (.412 BC, tipped, lead-free) and 160gr MRX (.439 BC, tipped), Hornady 139gr SST (.486 BC tipped) and 154gr Interbond (.525 BC, tipped), Nosler 140/150/160gr Partitions (.434-.475 BC), Sierra 150gr GameKing (.436 BC, SP), Speer 140gr Trophy Bonded (.360 BC, SP) … to name just a few. Whether you want an explosive ballistic-tipped bullet, high sectional density for penetration, or a bonded core for high weight-retention, you will find a 7mm bullet design that does the job exceptionally well.

7mm bullets
Bullet photos by B. Litz (above) and JeffVN (below right).

7mm bulletsHigh-BC Match Bullets
While hunters can be overwhelmed by the variety of good 7mm bullets available, long-range match shooters can concentrate on a half-dozen superior designs in the 160gr and up range. There aren’t that many premium match designs on the market, but the best ones available, such as the Berger 180gr VLD, are truly superior. The Berger 180gr VLD, with its amazing 0.684 BC, is one of the finest long-range bullets ever made…in any caliber. The Sierra 175gr MatchKing is also a proven performer in long-range and F-Class matches. It has a tough, durable jacket that can handle the high velocities generated by the short- and full-size 7mm magnum cartridges. Also, don’t overlook the 0.625 BC Hornady 162gr A-Max. This is a very accurate bullet that can be driven faster than a 175 or 180. Ace .284 Win shooter Jerry Tierney reports that Hornady’s 162gr A-Max was “extremely accurate” and was perhaps the best short-line bullet he tested. The 162gr A-Max is also an excellent choice for High Power Silhouette shooters.

The 7mm Advantage–High BC and Acceptable Recoil

Analysis of the 7mm Caliber for Long Range Shooting

by Bryan Litz

Caliber selection is a combination of science and preference. Everyone weighs the pros and cons differently for their particular application. The following is my take on the advantages of the 7mm caliber for long range target shooting.

7mm Ballistic Performance
There are several heavy, high-BC match bullets offered in 7mm including the 175gr SMK, 180gr JLK and Berger VLDs. Berger claims a 0.684 BC for its 180gr VLD bullet. There are no bullets of a smaller caliber that have higher BCs than these 7mm bullets. The following table shows the ballistic advantages of 7mm cartridges.

Comparative Ballistics (Drop from 100-Yard Zero, Drift in 10 mph Crosswind)
Cartridge Bullet Vel FPS 300yd Drop/Drift 600yd Drop/Drift 1000yd Drop/Drift
7mm WSM 180gr Berger VLD 3000 9.75″ | 3.83″ 63.81″ | 16.13″ 235.19″ | 49.31″
7mm SAUM 180gr Berger VLD 2970 10.02″ | 3.87″ 65.38″ | 16.38″ 240.81″ | 50.10″
.284 Win 180gr Berger VLD 2830 11.31″ | 4.10″ 73.27″ | 17.69″ 269.88″ | 54.26″
7mm-08 168gr Berger VLD 2670 13.32″ | 4.67″ 85.03″ | 20.39″ 317.97″ | 64.04″
.308 Win 175 Sierra MK 2690 13.84″ | 6.24″ 91.58″ | 27.64″ 365.74″ | 89.24″
6.5-284 142 Sierra MK 2950 10.42″ | 4.48″ 69.25″ | 19.52″ 263.08″ | 61.02″
.243 Win 115 DTAC 3120 8.97″ | 4.24″ 60.82″ | 18.25″ 232.3″ | 57.0″


Drop and Wind-Drift calculated with Point-Blank Software for 70° F temp, and 1000′ altitude. As claimed by manufacturers, BC values are: 0.684 for 180gr 7mm Berger VLD, 0.643 for 168gr 7mm Berger VLD, 0.608 for 175gr 7mm SMK, 0.595 for 142gr 6.5mm SMK, 0.496 for 175gr 30-cal SMK, 0.585 for 115gr 6mm DTAC.

7mm 30-caliber BC bulletsWith moderate charges in medium-sized cases like the .284 Winchester, these heavy bullets can easily reach 2800 fps. At this speed, the high BC 7mm bullets have less wind drift than all but the most extreme smaller caliber chamberings. [Editor's Note: With the recent introduction of Reloder 17 powder, a standard .284 Win can drive the 180s at 2950 fps, and the .284 Improved can reach 3050 fps with a long barrel.] In other words, anything smaller than 7mm has to be pushed really hard in high-pressure/short-barrel-life chamberings in order to match the ballistic performance of the heavy 7mm bullets at moderate pressures and velocities. In order to match the BC of the heavy 7mm match bullets, .30 caliber bullets of similar profile would have to weigh about 210 grains. That’s just to match the BC. In order to match the wind drift, the 210gr, .30-caliber bullet would have to have the same muzzle velocity of 2800 fps. That kind of speed is attainable with the largest .30 caliber chamberings, but this leads to the next consideration: recoil.

Recoil Considerations
Recoil can be considered the ‘preference’ part of the analysis. Everyone has their own thresh-hold for what a ‘comfortable’ or ‘tolerable’ level of recoil is. The 175-180 grain 7mm bullets at 2800 fps produce about the same amount of recoil as a .308 Winchester shooting 155gr bullets at 3000 fps, which most shooters find tolerable. In order to match the ballistic performance of the heavy 7mm bullets, a 210gr, .30-caliber bullet at 2800 fps generates 17% more recoil. Again, that’s 17% more recoil just to match the performance of the 7mm. The .30 caliber is capable of launching heavier bullets at higher speeds, but few people can honestly withstand that kind of recoil.

7mm Wind Drift Ballistics

Conclusion
At the large caliber end of the spectrum, ballistic performance is excellent but the recoil is prohibitive. At the small caliber end of the spectrum, recoil is pleasant but ballistic performance suffers. Many shooters, including myself, find that the best compromise between ballistic performance and recoil lies right on the moderate capacity 7mm chambering using heavy bullets. Each shooter has a unique tolerance for recoil, and should make the most efficient use of the energy that’s available within their ‘recoil budget’.

Bryan Litz is the current NRA National Individual Palma Champion. In 2008, he won three Long Range NRA regional tournaments (MI, PA, and TN), as well as the Midwest Palma championship. He was a member of the winning Team USA at the 2008 Spirit of America match. Bryan, an air-to-air missile design engineer for the US Air Force, also runs a consulting business,’Applied Ballistics, LLC’, that provides ballistics testing, software development, and bullet design analysis.


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7mm-08 Rem

7mm-08 cartridge diagramVersatile, Accurate Round Ideal for Hunting and Metallic Silhouette

When the U.S. Military looked to replace the venerable 30-06 in its battle-rifles and machine guns, it came up with the 7.62×51 NATO, aka .308 Winchester in civilian guise. The .308 Win is a great cartridge, but, in some respects, the 7mm-08 is better. The 7mm-08 is a necked-down version of the .308 Win. With the exception of neck diameter, the 7mm-08 is virtually the same dimensionally. But when you compare heavy bullets, grain for grain, the 7mm-08 offers better ballistics. In other words a 168-grainer fired from a 7mm-08 will exhibit less drop and less windage than a 168gr bullet fired from a .308 Win. The 7mm-08 enjoys most of the advantages of the .308 (inherent accuracy, long barrel life, excellent terminal performance) while offering better ballistics grain for grain.

These qualities make the 7mm-08 a very popular deer-hunting round. The combination of knockdown power, excellent ballistics, and reduced recoil (compared to a .308 shooting bullets of comparable BC) has also earned favor with Metallic Silhouette shooters. The 7mm08 has first-class accuracy and enough hitting force to knock down the heavy rams even at 500 yards.

Among benchrest or F-Class shooters, the 7mm08 is not commonly used. It is “too much cartridge” for hunter benchrest. In the F-Class game, it is completely overshadowed by the .308 Winchester because the .308 is one of the two cartridges officially allowed in F-TR class. You could bet, however, if the F-TR rules allowed the 7mm-08, many shooters would make the switch. In F-Open, the 7mm-08 has been passed over in favor of the 6.5-284, .284 Win, and short magnums. Reason being, with the 22-lb weight limit, it’s better to use a bigger cartridge that can push the big 7mms to higher speed–otherwise stick with something like a 6.5-284 which has substantially less recoil.

Bullet Selection for Various Duties
7mm-08 Remington Silhouette shootingYou’ll find quality 7mm bullets for any purpose you can name: varminting, game-hunting, silhouette, and long-range shooting. Selecting the right bullet for the task is the hard part. For match shooting, the 7mm-08 doesn’t really have the boiler room to push the heavy 175-180gr bullets efficiently, so we suggest that paper-punchers concentrate on the 150-160gr class. The plastic-tipped 162gr A-Max has proven to be very accurate, with an impressive 0.625 BC. This A-Max bullet, and the 150gr Sierra MK, are also very popular with silhouette shooters. Deer hunters should be happy with one of the advanced-design bullets in the 130-140gr class, such as the Hornady 139gr Interbond, Nosler 140gr Partition, and Barnes 140gr Tipped TSX. The TSX is a lead-free design, offering hunters a quality projectile to use in areas where lead-core bullets are prohibited. The 7mm-08 can comfortably launch 130-140 grainers in the 2850-2900 fps range, with sporter-length barrels.

Brass Options and Case Prep
7-08 reloadingNorma, Remington, and Winchester all make 7mm-08 brass. Of these three, we recommend the Winchester. At about $42.00/100 it is less than half the cost of Norma brass. We’ve received many good reports about Remington brass, but, typically, it will require sorting into two or three batches according to neck-wall thickness. Many 7mm-08 shooters prefer to use necked-down .308 Winchester brass, either because they have an existing supply of .308 cases or because they prefer using Lapua brass. If you dont mind necking down .308 Win cases, Lapua is the way to go. Lapua brass is more consistent than domestic brass (in weight and neck-wall thickness), and Lapua cases can normally be loaded at least a dozen times. Lapua brass is more costly than domestic brass, but at $58.99/100 (Grafs.com price), it is still a good value when you consider that it may have twice the reloading life of lesser brands. We know some High Power shooters who have loaded their Lapua .308 Win cases over 30 times, annealing after 8-10 loads.

7mm-08 Chambering Issues
Many 7mm-08 shooters use this round in factory rifles with “ample” SAAMI-spec chambers. Factory chambers are often cut with an excessive amount of clearance at the neck-shoulder junction. Given this kind of chamber (and the case’s shallow 20° shoulder angle), the brass can build-up at the base of the necks (on both the inside and outside). You may find, in short order, that, the force required to seat your bullets goes up. One solution is to turn the bottom third of the case-neck, but then you’ll end up with more clearance between the neck and the chamber, so the brass will eventually migrate back. One work-around is to choose bullets with relatively short bearing surfaces so you can keep the base of the shank well above the neck-shoulder junction. You can also seat your bullets farther out, subject to mag-length limitations.

7mm-08 Load Map
Powder Grains Primer Bullet Velocity Comments
VV N140 38.4 Fed 210M 168gr Sierra MK 2500 Sierra Accuracy Load. 2.790″ COAL.
IMR 4064 40.3 CCI BR2 162gr Horn
A-Max
2670 J. Scherrer HP Silhouette load for ram.
Win 760 45.0 Win LR 154gr Horn SST 2690 Accurate, half-moa hunting load. Great, High-BC bullet.
IMR 4064 38.0 CCI BR2 150gr Sierra MK 2570 J. Scherrer HP Silhouette load for
chicken, pig, turkey.
RL 15 39.5 Fed 210M 150gr Sierra SP 2700 Sierra Hunting Load. 2.780″ COAL. Very Accurate.
Varget 42.0 CCI 200 140gr Nosler
Accubond
2840 Great hunting choice: “Awesome on deer and hogs”.
IMR 4064 42.5 CCI 200 139gr Horn
SP
2850 Bullets in lands get one-hole groups. Speeds over 2900 mv in some barrels.
RL 17 48.5 C Fed 210M 130gr BTSP 3107 Fed Brass. Alliant Load Data. 2.730″ COAL.
IMR 4064 42.5 Fed 210M 130gr Sierra MK 3000 Sierra Max load. Good accuracy jamming or jumping.
RL 15 45.0 Fed 210M 120gr Horn
V-Max
3100 Good velocity, near 100% fill density with RL 15. Jump .015.
Win 748 45.6 Fed 210M 100gr Sierra HP 3200 Sierra Accuracy Load. Meters great. 2.685″ COAL.
WARNING: With all loads, ALWAYS START 10% LOW and work up incrementally.

.284 Winchester

.284 Winchester cartridge diagram.284 Winchester–The Original May Yet Eclipse the 6.5-284
The .284 Winchester is an efficient cartridge, offering performance of a 30-06 sized case with a much smaller form factor. With the latest ultra-high-BC 7mm bullets from Berger, JLK, Sierra, and Bob Cauterucio, the .284 Win has match-winning capability from 600 to 1000 yards. The accuracy is there and the ballistics trump any popular 6mm or 6.5mm chambering.

For hunters, the .284 is also a great choice. A .284 Win is the biggest cartridge you really need to hunt all but the largest North American game. The case will drive 150-170 grain hunting bullets with plenty of knockdown power. An old maxim says “Accuracy is all about the 3Bs: barrels, bullets, and brass.” Well, when it comes to bullets and brass, the .284 is at the top of the heap. The current generation high-BC 7mm bullets are as good as anything every made, and the brass—either Win-brand .284 or Lapua 6.5-284–is likewise outstanding.

Brass Options and Case Prep
Only one company makes .284 Winchester brass–namely Winchester. However high-quality 6.5-284 brass is offered by Lapua and Norma. Right now, most accuracy-oriented .284 shooters are using necked-up Lapua 6.5-284 brass. It is very uniform, and stands up to high pressures better than other brands. Winchester-brand brass is an excellent “second choice” and some good shooters prefer it to necked-up Lapua or Norma 6.5-284 brass. John Hoover, who shoots a 6.5-284 using Winchester cases, believes that early lots of Winchester brass are better than anything else available. Winchester .284 brass is certainly very strong. Jerry Tierney has done extensive testing with both Winchester-made .284 brass and necked-up Lapua 6.5-284 brass. In Jerry’s F-Class rigs, the Win brass shot as accurately as the Lapua brass. Neither brand had a distinct accuracy (or velocity) edge. However, Jerry says the Lapua brass “definitely lasts longer” and the Win-brand brass “would benefit from annealing” after a half-dozen loadings.Another factor to consider is cost. The Winchester brass can be obtained for half the cost of Lapua or Norma. With any brand of brass to be used in a .284 Win, you’ll need to inspect the brass, and prep the cases.

Powder Selection for the .284 Win
For .284 Win Shooters using 175-180gr match bullets, the powder of choice is Hodgdon H4831sc. This delivers superb accuracy, good velocity, and ultra-low ES/SD. H4831sc also fills up the case very nicely. The “next generation” heavy-bullet powder may be Alliant Reloder 17. It definitely yields 125-150 fps more velocity than H4831sc with 180-grainers. Hodgdon Hybrid 100V also promises enhanced velocities–but the gain is not as dramatic as with RL 17. For hunters, shooting 145-160gr hunting bullets, there are a half-dozen powders that work very well, such as: H4831sc, Hybrid 100V, H4350, Ramshot Hunter, Reloder 22, Vihtavuori N560, and Winchester 760. The new Winchester Supreme 780 can also be used to reproduce factory Winchester 160-175gr hunting loads.

Advanced .284 Win Accuracy Tips
Charles Ballard, reigning 2008 F-Class Champion, is a leading .284 Accuracy guru. His reloading methods, described in his Gun of the Week feature, have produced amazingly good ammo. At 1000 yards, the vertical on his loads is amazingly tight. Over the chronograph he has achieved ES under 7 and SD in the low single digits (see CHRON VIDEO below). Read the article for all Charles’ secrets, but very careful brass prep is key. Pointing bullets using the Whidden Pointing system can also reduce vertical at long range. Chambering can play a role as well. Jerry Tierney, a past NBRSA 1000-yard champion and .284 Win “guru”, has observed that overly tight chamber neck tolerances can cause accuracy problems. Jerry says “some guys who were running minimal neck clearance .284 chambers weren’t getting the accuracy they expected. If you open up the neck to allow more clearance, say .0015-.002″ per side, that seems to solve the problems. I can’t tell you exactly why–maybe it allows a ‘cleaner’ bullet release–but easing the neck clearance has helped many .284 shooters get better results.”

More Speed — Reloder 17 and the .284 Shehane

In recent years, frustrated with poor barrel life in 6.5-284s, many shooters have experimented with the “straight .284″. Charles Ballard has had spectacular success with the .284 Win using a 32″ barrel. However, others have been a little disappointed with the .284′s velocities with heavy 175gr and 180gr bullets. Shooters want to get these high-BC projectiles up to 2950 fps (or faster), but most folks fall short, with velocities topping out at around 2820-2850 fps.

2950 fps from standard .284 Win and 3050 fps from .284 Improved

Today, the 2950 fps goal IS achievable with 180s using the recently-released Reloder 17 powder from Alliant. That’s big news for 7mm fans. This new propellant is nearly ideal for the .284 Win shooting the heavy 7mm bullets. Using RL 17, you can get 2950 fps fairly easily in a standard (non-improved) .284 Win case. Robert Whitley’s tests have shown that.

But 2950 fps isn’t the end of the story. Two years ago Bill Shehane wildcatted an improved version of the .284 Winchester. The changes were modest, and no special case-forming was required. Neck length and shoulder angle are unchanged. Basically, Bill just reduced the case’s body-taper about .010″. That adds enough case capacity? (+3.35 grains) to drive 180s at 2950 fps with H4831sc or similar powders. And with RL 17 you can go faster…a LOT faster.

.284 Win Improved Shehane

Reloder 17 Test Results in .284 Shehane

Alliant Reloder Reloader 17High power ace Jim Hardy fields a .284 Shehane in long-range matches. According to Jim, in cool weather, his .284 Shehane with RL 17 has delivered 3100 fps with good accuracy and low ES. In warmer weather, he figures 3030-3050 fps with 180s is the MAX, and that is probably going to prove more accurate than 3100 fps. Nonetheless, the fact that the .284 Shehane can now deliver short-magnum-class speeds (using 10 grains LESS powder than a WSM) is big news–and a real break-through. Jim reports:

Field Test (October 26): “I have been testing RL-17 in my .284 Shehane rifle with a Barnard ejectorless action. Today’s chrono testing with 55.0 grains of RL-17, Lapua brass, 180 JLK, and Russian primers yielded about 3030 fps with an ES of 14. The temperature today was in the 50s. This is the same load (except 180gr Berger instead of 180gr JLK) that ran 3100 fps in my old Broughton barrel on my Gilkes-Ross (GR) action. That 3100 fps load showed a little pressure but no hard bolt-lift.

The brass from the Barnard and the new Broughton barrel shows almost no pressure signs on the case head at 55.0 grains and the primers are still not flattened against the sides of the pockets. It looks like it could go another grain. I will test carefully. NOTE–The ES is coming down with the higher nodes. There seem to be three nodes with the 284-based chamberings: 2825-2850, 2925-2950 and I believe (if RL-17 comes through) 3025-3050.”

Field Test (October 31): “As stated before, the new Broughton on my Barnard is MUCH slower than the one on my Gilkes-Ross, but the Barnard is showing no hard bolt-lift and the 56.0 grain charge still leaves the primers looking good. I know that shooting in 50° temps is a world away from 105° at Butner, but the RL-17 numbers are starting to get my attention. My 55.5 grain charge gave me 3060 fps with an ES of 22. The 56.0 grain charge gave 3078 fps with an ES of 12. The primers look better than the 55.0 charge of RL-17 or the 57.0 grain charge of H4831sc in my GR rifle. It probably has something to do with the floating pin in the Gilkes-Ross action vs. the small pin in the Barnard and the fact that all three lugs on any Barnard seem to have 100% contact.

Field Test (November 2): “Well, I now know the limits of the .284 Shehane and RL-17. It was a beautiful day for testing at about 72°. I had six rounds left of my 55.5 grain load from October 31st with the 180 JLKs. This chron’d at 3054 fps Mean, 14 ES, 7 SD. As an aside, I noticed that RL-17 started to shoot cleaner on the case necks and the bore as I got above 55.0 grains.

Hitting the wall–Since the 56.0 grain charge showed no pressure problems the last time out at 3078 fps, I tried 56.5. The first two shots went 3126 and 3118–with a blown primer on the first and a smoked primer on the second. That was enough for me. Yes, you can run the .284 Shehane at 3100, but that is not a safe place to be. I would call 56.0 grains (for 3078 fps) the MAX, but that load would have to be adjusted down for hot weather. I believe that accuracy and ballistics will be optimal in the 55.0 to 55.5 range (3030 to about 3060 fps).

The bottom line is that RL-17 will give me a safe 100 fps over the 2951 fps generated from my match load of 57.0 grains of H4831sc under a 180gr VLD. I suspected 3030-3050 fps would be the ‘sweet spot’, and that appears correct. I will continue to test for accuracy. That will determine the winner for me. If I can get the ES down to single digits with long-range accuracy (that matches H4831sc) at 3020+ fps in all temps, I may go with RL-17. Yes, RL-17 is very fast, but my 2950 fps H4831sc load will absolutely hammer in all conditions. Another 50 or even 100 fps will not get me to switch unless I can get the same accuracy in all conditions.”

.284 Shehane Case Capacity: Out of a sample of 10 fire-formed 284 Shehane cases vs. 10 virgin Lapua 6.5×284 cases necked-up to 7mm, the H20 capacity of the 284 Shehane was 68.25 grains. The virgin .284 brass was 64.9 grains. The average difference in the case capacity is 3.35 grains in favor of the 284 Shehane. That extra 3.35 grains sure makes a difference and it seems like the ‘improved’ case capacity is just about ideal for the 180s and Reloder 17.

.284 Winchester Load Map
Powder Grains Primer Bullet Velocity Comments
H4831sc 54.5 CCI BR2 180gr Berger VLD 2890 Lapua brass. Ballard (F-Class Champ) match load. 32″ bbl. Accurate. Single-digit ES/SD.
H4831sc 53.0 CCI BR2 180gr Berger VLD 2810 Lapua brass. Tierney data. 30″ bbl. Very accurate 0.3 MOA, SD=6. Soft seat Bergers into lands.
H4350 50.7 CCI BR2 180gr Berger VLD 2825 Winchester brass. Litz match load. Moderate. 2825 fps from a 30″ barrel. Very low SD.
RL 17 52.0 CCI BR2 180gr Berger VLD 2953 Winchester brass. Whitley test load. Not Max. Seated .010″ in lands.ES 19, SD 7.
H4350 51.0 CCI 200 175gr Sierra MK 2822 Lapua brass. 30″ bbl. Jumping .015″, .002″ neck tension.
VV N160 54.3 Rem 9.5 168gr Sierra MK 2800 Sierra Max Load. 2.800″ COAL.
H4350 50.5 CCI BR2 162gr Horn
A-Max
2910 Lapua Brass. 30″ bbl. Good F-Class load. Bullets worked best in lands.
Hybrid 100V 54.0C CCI 200 162gr Horn BTSP 2864 Hodgdon Max Load. 2.970″ COAL.
RL 19 53.0 Fed 210M 154gr Horn
Interbond
2900 Win Brass. Alan R. hunt load. Good vel in short barrels.
Varget 48.3 Rem 9.5 140gr Sierra SBT 2900 Sierra Hunting Load. 2.800″ COAL.
H414 55.0 CCI 200 139gr Horn SST 3075 Hodgdon Max Load. 2.915″ COAL.
WARNING: With all loads, ALWAYS START 10% LOW and work up incrementally.

CALIBER CHOICE: The Case for the .284 Win

by Charles Ballard

Comparative Ballistics: 6.5-284, .284 Win, and 300 WSM
For shooters who are not sold on the .284 Winchester, I give you a real-world ballistics shoot-off. We comparison-tested a 6.5-284 rifle launching 142 SMKs at 2975 fps, a 300 WSM rifle firing 210 Bergers at 2850 fps, and my .284 Winchester shooting 180 Bergers at 2900 fps. We had three shooters and each rifle was fired simultaneously with no-wind zeros on three separate targets set at 1000 yards. The shooters then exchanged rifles and we repeated the test a couple times. The 6.5 and 300 stayed consistently within an inch of each other. But my .284, with its high-BC Berger 180s, shot inside both the 6.5 and 300 by at least 3″ every time. BC rules in the wind. I was sold!

.284 Win F-Class

Cost Comparison: .284 Win vs. 6.5-284
The cost of reloading the .284 Win is roughly $.07 more per round than that of the 6.5-284. The .284 uses a grain or two more powder than the 6.5-284, and 7mm bullets cost about $6.00 more per 100-count box. However, to truly compare the cost of shooting the two calibers you must figure in barrel life. My 6.5-284 barrel went south at 900 rounds. My .284 barrel now has 1,036 rounds, and by all indications it will shoot well to 3,000+ rounds. For cost comparisons sake, lets use 1,200 rounds for the 6.5-284 and 3,000 rounds for the .284 Win. The average cost of a barrel, chambered and fitted, is $500.00. Using these figures, the barrel cost of a .284 Win is $.17 per round vs. $.42 per round for the 6.5-284. That’s a $.25 per round difference, equivalent to a 60% savings for the .284.

OK, if we now net the barrel cost savings (-$.25) for the .284 with the higher cost of 7mm reloading components (+$.07), I figure the .284 Win costs $.18 per round LESS to shoot than the 6.5-284. Over the span of 3,000 rounds, that’s a $540.00 savings.

Gun Handling and Recoil
If there is a down-side to the .284 it would be recoil. Now dont get me wrong, at 22 pounds with a decelerator recoil pad, the .284 is comfortable to shoot. The recoil difference between the 6.5-284 and the .284 is about the same as the difference between a 6x250AI and a 6.5-284. In the versatility section I will elaborate more on this subject.

Ease of Load Tuning
Despite the issues I explained in the load development section with low initial velocities on new barrels, I would say the .284 is fairly easy to tune. The barrel with which I shot my record was removed after that match so I dont put too many rounds on it before the Nationals. The new barrel on this rifle was tested using the same load. As with the first barrel, the second barrel yielded 2775 fps with a “starter load” of 53.0 grains of H4831sc. With only 11 rounds through the new tube, I shot a 600-yard match on June 22, 2008. I loaded 44 rounds using 55.0 grains of H4831sc. This load ran at 2825 fps. After my first string this load started hammering. I shot a 200-7X with no elevation change on my last string.

Multi-Discipline Versatility
The .284 is my hands-down choice for shooting F-Class. I recently shot my first 600-yard benchrest match. I shot the .284 Win in heavy gun. In this match I found the first weakness in my beloved .284. On a bench you do notice the recoil. The 6mmBR pilots could run off five shots before I could shoot two. My groups were respectable: a four-group, 3.055″ Agg. But, the added recoil of the .284, even with front and rear rests aligned, took me off target. All this being said, if a man wanted just one caliber for F-Class, long-range benchrest, and hunting, I would still suggest the .284 Win.

7mm WSM

7mm WSM cartridge diagramStrong, Modern Case That Can Drive Big Bullets at 3000+ fps.

Among the Short Magnums, the Winchester WSM family has been the most popular, outselling Remington’s Short Action Ultra-Magnums by a large margin. Both the 300 WSM and 7mm WSM have been popular with long-range shooters, given the excellent selection of match-grade bullets in both calibers. In addition, many shooters have chosen to campaign a 7mm-270 WSM or 7mm-300 WSM wildcat, using the 270 or 300 WSM brass necked to 7mm. The 270 and 300 versions both have a slightly longer neck and slightly less capacity–both desireable things. However, some guys do prefer having the extra “boiler room” of the true 7mm WSM. Jeff Van Niel reports: “I shoot a true 7WSM, not a wildcat 7/300 or 7/270. I find the necks are long enough to do what I need to do, and there is enough extra available capacity to ramp mine up one more notch on the velocity side if I ever decide that 2,940 fps with the Berger 180 is too slow!”

British shooter Vince Bottomley has used the 7mm-300 WSM with great success, setting new United Kingdom records. Vince’s load was the Berger 180gr VLD pushed by Reloder 25 powder. In this section we cover both the “normal” 7mm WSM and the 7mm-270/300 WSM variants.

Brass Options and Case Prep
Winchester is your only choice for ready-to-go 7mm WSM cases. However, Norma makes both 270 WSM and 300 WSM brass, which can be easily necked into 7mm WSM cases. Both Winchester and necked-up/down Norma brass works very well. Out of the box, the Norma is more consistent in weight, and the necks are more uniform. However, you can buy 100 Winchester-brand cases for $35.00 or less, while the Norma brass will run $90.00 per hundred or more (the 300 WSM seems to be a little cheaper than the 270 WSM currently).

7mm WSM reloadingIF you are prepared to sort and prep your brass carefully, the Winchester-brand brass can perform as well as Norma, by most reports. But the culling process is time-intensive. First you should weight-sort the brass, then check the neck thickness, culling cases that are way out of wack. For match purposes, we recommend neck-turning the Win-brand cases. This will ensure uniformity AND it can give you a thinner neckwall. Some shooters feel that the necks on Win-brand brass are too thick out of the box. Thinning them can make neck-tension more consistent and reduce ES and SD. The shooters we know that are using domestic WSM brass successfully in long-range benchrest competition turn their necks. With Win-brand brass it is also a good idea to inspect the primer pockets and uniform them if necessary.

7mm WSM vs. 6.5-284, and Winchester Brass

Jeff Van Niel tells us: “I’ve owned and shot both the 6.5-284 and 7 WSM. They are [both] excellent choices. You’ll likely get better barrel life on the 7 WSM, but it does recoil more than the 6.5-284. I’m currently shooting the 7 WSM for F-Class at 600 yards and 1K. Although the brass is not as uniform as Lapua, it is also HALF the price.

I prepped and sorted my cases, and have no problems with accuracy using Winchester brass. I anneal my brass every third firing, and it lasts for about nine (9) loads before I toss it. In F-Class I put 55-60 rounds through my 7 WSM in a day, 22-25 rounds at a time in less than 15-18 minutes. Even then, I have 925+ competition rounds through her and she looks good at the throat and shoots like crazy. I’ve got another 7 WSM coming–this one tight-necked. The 7 WSM is a great chambering.”

With Norma brass, we’ve found you can pretty much shoot it out of the box. Given the cost of brass and bullets, however, we would do at least a “clean-up” pass on the necks to ensure they are uniform. Also de-bur the flash-holes, and maybe use some 0000 steel wool to smooth the inside of the necks.

Necking-Up vs. Necking-Down
For Norma brass users, which is better to start with–the 270 WSM or the 300 WSM? Well, some people think it’s better to neck UP, because the expanding mandrel pushes neck-wall thickness variations to the outside (which you can then neck-turn away). Others prefer necking DOWN because they think this is less likely to cause run-out problems and form doughnuts at the neck-shoulder junction. Remember, when you neck UP brass you are making neck from thicker-profile shoulder metal. This, normally, leaves the brass thicker at the base of the neck–an incipient doughnut. The opposite is true when you neck DOWN brass. Accordingly, we recommended necking down the 300 WSM brass. Also, Norma 300 WSM brass is currently cheaper than Norma 270 WSM brass.

Powders and Primers
With the heavy bullets, slow powders such as H1000, H4831sc, Reloder 25, Norma MRP, and Ramshot Magnum work best. Reloder 25, a high-energy, double-base powder, is near the top of the charts in velocity. However, H4831sc has a reputation for great accuracy and it can deliver super-low ES and SD in properly prepped brass. The new Reloder 17 is worth trying if you’re looking to extend your velocity range upwards.

While the WSM case requires a Magnum-sized boltface, it uses a conventional, large rifle-sized primer. (Magnum LR primers offer more spark but they are the same size.) We’ve heard good results with CCI, Federal, Remington, and Wolf (Russian) large rifle primers–both regular and magnum versions. You may want to experiment with both regular and magnum (extra energy) to see what works best with your choice of powders. Normally CCI is a top choice for shooters running very hot loads. This is because CCIs have harder cups than other brands and can stand higher pressure loads before they crater. This is not a major concern with the 7mm WSM, however. The case has abundant capacity, so you don’t have to drive the case at max pressures in order to get 175-180gr bullets to 2950 to 3050 fps–the most accurate velocity range. Some shooters have experimented with a “high node”, up past 3150 fps, but this runs the risk of bullet blow-ups. You don’t need the speed–even at 3000 fps, a Berger 180 VLD has superb ballistics and will shoot inside most anything else you’ll see at a long-range match.

7mm WSM reloadingProducing Better WSM Ammo
Here are some advanced reloading tips gathered from successful 7mm WSM shooters.

1. Turn the necks, particularly with Winchester brass. This will help with neck-wall uniformity and bullet release. WSM cases need adequate neck clearance in the chamber for bullet release. Total Clearance of .003″-.004″ (both sides combined) will probably better than .0015″ or less.

2. Make sure you have sufficient clearance between the neck and the side of the chamber. Some guys running with super-tight clearance on the necks had persistant and frustrating accuracy problems and unexplained flyers. Adding neck clearance (by turning the necks) cured the flyers. Three or four thousandths total clearance (sum of both sides) will probably work better than one-thousandth.
3. Proper case-mouth chamfering is very, very important for accuracy and optimal ES and SD. With these long bullets you want the entrance to the case mouth as perfect as possible.

4. Experiment with shooting the VLDs OFF the lands. While the 180gr VLDs, typically, work best seated .010″ or more into the lands, some shooters have obtained excellent accuracy jumping their bullets .020″ or more. It’s worth trying.
Very low ES/SD is possible

5. WSM brass really stiffens with time. For best results you may need to adjust neck tension (switch bushings) after a few reloadings. Annealing can also help after four or five reloading cycles.

7mm WSM Load Map
Powder Grains Primer Bullet Velocity Comments
H1000 66.5 Fed 210M 180gr JLK VLD 2900 Win Brass. 1/4″ at 100 yards. Near Max. 2.312″ Base to Ogive.
H1000 66.2 Fed 215 Mag 180gr Berger VLD 2950 Win Brass. Good load (1/3 MOA) for LR precision or tactical matches
IMR 7828 ssc 63.50 Fed 215 Mag 180gr Berger VLD 3010 Slightly more Velocity than H1000.
Norma MRP 63.0 CCI 250 180gr Berger VLD 3000 Accurate Load. Charge weight varies with powder lot.
H4831sc 61.0 WLR 175gr Sierra MK 2830 R. Horst LR load. Win Brass. Ultra-accurate in 9-tw Broughton 5C barrel.
Win S780 63.0 Fed 215 175gr Speer MagTip 2850 Hodgdon Max load, .2.760″ COAL, 60.5K psi.
RL 22 62.2 Win LRM 168gr Sierra MK 2850 Sierra Accuracy Load, .2.830″ COAL.
Win S780 67.5 CCI 250 168gr Sierra MK 2940 Hodgdon Max load, .2.850″ COAL, 3200 ft/lbs.
H4831sc 64.0 WLR 162gr Horn
A-Max
2950 R. Horst hunting load. Win Brass. Accurate in 9-tw Broughton 5C barrel.
H4350 63.0 Win LRM 150gr Sierra BT 3100 Sierra Hunting Load, .2.815″ COAL, 61K psi.
RL 17 63.5 Fed 215 145gr BTSP 3166 Alliant Load Data, 2.760″ COAL.
H4350 69.0 Win LRM 120gr Sierra SPT 3400 Accurate, Low ES/SD, hunting/varmint load, .2.795″ COAL.
RL 25 66.0 Fed 215M Mag 180gr Berger VLD 3050 Norma Brass. Bottomley 7mm-300 WSM load (smaller capacity case).
VV N570 n/a Fed 215M Mag 180gr Berger VLD 3000 Norma Brass. Bottomley 7mm-300 WSM load (smaller capacity case). Good Velocity but accuracy better with RL 25.
WARNING: With all loads, ALWAYS START 10% LOW and work up incrementally.

The 7mm-300 WSM — A Champion’s Perspective

Editor’s Note: Vince Bottomley is one of the UK’s top bench shooters (at all distances) and he recently set a British record at 1000 yards using a variant of the 7mm WSM. Vince’s 7mm-300 WSM drilled a 2.670″; group to eclipse a 5-year-old UK record. Vince started with Norma 300 WSM cases, and then necked them down to .284. The reason to start with the 300 WSM is that this case has a slightly longer neck and slightly less capacity, making the 7mm-300 WSM a more efficient solution. With this cartridge, shooting Berger 180 VLDs, Vince can attain 3050 fps easily. He finds this speed to be optimal with the Berger 180s, as he explains below. Vince’s rifle features a BAT ‘M’ (medium) action, Bartlein barrel, and a tight-neck chamber cut with a Pacific Tool & Gauge reamer. The gun has proven very accurate–Vince has had two groups under three inches at 1000 yards using Norma brass, Berger 180s, and Reloder 25.

Tips on Loading for the 7mm-300 WSM

by Vince Bottomley

7mm WSM Reloder 25

For my 7mm 1000-yard gun, I chose a 7mm-300 WSM. My cases were formed by necking-down Norma-brand 300 WSM brass. I have tried a few powders, and Reloder 25 was the most successful. I had my best groups using around 66 grains but this can vary by up to 2.0 grains depending on the batch of powder. It’s essential to buy enough powder for a full season otherwise you can easily waste 20 rounds developing a new accuracy load. (This is not good when accurate barrel-life is only around 500 rounds!)

Like most of us, I’m a great Lapua fan when it comes to brass but of course, they don’t produce WSM cases so I selected Norma brass. Norma’s 300 WSM cases have proven to be excellent brass, very consistent in the neck-area. Cases were carefully prepped as for benchrest and turned to give 0.310 inches across the neck of a loaded round and trimmed to the same length. I don’t think it pays to go a lot tighter than this with a 1000-yard benchgun, where rounds need to be thrown in very quickly when trying to beat the wind. I don’t bother batch-weighing brass anymore.

I’ve always used Berger 180gr bullets as this is what my PT&G reamer was ground to suit. They are very good right out of the box. I’ve found no need to weigh, trim meplats or sort by bearing surface length. Just take them out of the box and shoot ‘em! However, I found that around 3050 fps is the optimum velocity. If you drive them over 3100 fps and the odd one may ‘blow’! Vihtavuori powders are very popular in the UK (and cheaper than US powders) and the powder is very consistent from batch to batch. However, Vihtavuori N170 would not give me sufficient velocity even with a full case but Vihtavuori N570 gives good velocity but I could never quite match the accuracy obtained with the Reloder 25. Having said that, the barrel was in its second season and was definitely on the way out.

Experiments with a 6.5-300 WSM

I’ve also built a 6.5 WSM. Again, I formed the brass from the 300 WSM case (slightly longer neck, less capacity than the 270 WSM). Reloder 25 again gave excellent results. Accuracy was not in the same league as the 7mm WSM but I was using 139gr Lapua Scenars (moly’d) and the rifle was built for F-Class, not 1000-yard benchrest. The load was about the same–66 grains of RL25. But velocity was much higher. My 6.5-300 WSM runs around 3450 fps. Remarkably, I have not ‘lost’ any of the 139gr Scenars even at this 3450 fps velocity.


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7mm Rem SAUM

7mm SAUM cartridge diagram7mm Rem Short Action Ultra Mag — Best of the Bunch?

WSM vs. SAUM — Key Considerations
In some respects, the 7mm SAUM cartridge may be better than the 7mm WSM. The 7mm SAUM holds less powder–but that’s a good thing, since the capacity is more than adequate to do the job. You can drive the 180s at 3000 fps with a SAUM using less powder than with a WSM. Additionally, the SAUM case has a slightly longer neck. This gives you greater flexibility in bullet seating. With a long neck you can set the throat so the long 180gr VLDs are above the neck shoulder junction, yet you can still seat shorter hunting bullets close to the lands. Additionally, long case necks, some believe, cause less throat erosion than shorter necks. That’s not “hard science” but it is certainly a view shared by many experienced shooters. The long neck is one reason many varminters favor the 6mm Remington over the .243 Winchester.

Better Brass Spurs Interest in 7mm SAUM
Among the 7mm short action Magnums, most interest had focused on the 7mm WSM until very recently. The WSM enjoys greater popularity with precision shooters because excellent 270 WSM and 300 WSM Norma brass is available and the 7mm WSM Win-brand brass was pretty darn good, once you turned the necks. Recently, however, Norma has started producing 300 SAUM brass. This can be easily necked down to 7mm.

Message to Readers: If you are considering a 7mm WSM (or 7mm-300 WSM) you should seriously look at the 7mm Rem SAUM as well. Now that Norma 300 SAUM brass is available it’s a whole new ballgame. And the 7mm SAUM really performs. 7mm WSM shooter Jeff Van Niel tells us:

“I will say this about the 7mm SAUM versus the straight 7mm WSM. I wish I had tried the SAUM before I committed to the 7mm WSM, it would have saved me a bunch of money on gunpowder so far. I shot with Steve Ikeda at last year’s Nevada Palma match and his 7mm SAUM is an absolute hammer. He was shooting with much less (at least 2 or 2.5 MOA) elevation than my 7mm WSM, and doing it with considerably less powder.”

7mm Remington SAUM brass Nosler'><b>Brass Options and Case Prep</b><br /> <br>Currently, you have three choices for SAUM brass--foreign (Norma) or domestic (Remington and Nosler). Norma is expensive, and currently only available in the larger 300 SAUM case, so you'll have to neck it down. But it's very good brass. <a href=Nosler 300 SAUM brass is also expensive ($55.95 for 50 cases), but Nosler claims it is weight-sorted and “prepped”. We have no reports yet, positive or negative, on the Nosler product. Given the cost, we’d buy Norma SAUM brass before Nosler.

The Remington 7mm SAUM brass, we’re told, is surprisingly good… but you’ll need to sort, cull, and neck-turn for best results. Forum Member Steven (“Bolo”) Ikeda has been shooting a 7mm SAUM successfully for a couple years. He has used Remington-made brass exclusively. He weight-sorts the brass, culling any pieces that are on the extreme ends of the bell curve. Then he runs the cases over a neck thickness gauge to identify cases that are much thicker or thinner than average. Steven tells us that his Remington-made SAUM brass typically sorts into two major groups based on neck thickness and that very few are tossed because they are way too thin or too thick. So, divide your brass into two groups, then weight-sort within those sub-sets.

Unlike the Winchester-made WSM brass, excessively-thick necks haven’t been a problem with Remington SAUM brass, so you could do a no-turn SAUM chambering, provided you sort the brass first. If you don’t sort the brass by neck-thickness, you should have at least .006″ neck clearance over the minimum diameter of a loaded round to ensure that ALL the brass will chamber. If you pre-sort the brass, you can get by with tighter tolerances. With Remington-made SAUM brass it’s not a bad idea to inspect cases carefully and ream the flash holes if necessary to make them consistent.

7mm Rem SAUM 180 Berger 175 Sierra 162 A-Max

Necking-Down Norma 300 SAUM Brass
With Norma SAUM brass, there’s not much you need to do but neck the cases down to 7mm from 30 caliber. Since this is a rather large reduction (from .308 to .284), you may want to do it in two steps. You can start with a 7mm SAUM body die from Redding. This has a bit of a funnel so the 300 SAUM necks go in smoothly, and will reduce in diameter part-way. Then finish with a neck-sizing die with appropriate bushing. Note: since the bushing won’t size the neck all the way down to the neck-shoulder junction, you should check your necked-down brass for fit in your chamber before you add powder and seat the bullets. If necessary, run the necked-down Norma brass through a conventional 7mm SAUM full-length sizing die. This last step will probably not be necessary, but you should definitely see if your brass chambers before you charge the cases and seat bullets.

Powder Selection for the 7mm SAUM
Preferred powders for the 7mm Rem SAUM (with heavy bullets) are the same as for the 7mm WSM: H1000, H4831sc, IMR 7828, Reloder 22 and 25, Vihtavuori N170, N560, N570, and Norma MRP. Reloder also 17 promises to be a very effective powder for the 7mm SAUM with some bullet weights, but we are still awaiting test results. We certainly expect RL 17 to deliver impressive velocities–the question remains, will it match the accuracy and low ES/SD of powders like H4831sc, H1000, and RL 25? We recommend, for a 7mm SAUM rifle shooting the 175gr MKs and 180gr VLDs, that you start with H4831sc, H1000, or RL 25, and then experiment with RL 17 AFTER you’ve established an “accuracy baseline” for the rifle.

7mm Remington SAUM S.A. Ultra MagnumCase Efficiency, Charge Weight and Barrel Life
The 7mm SAUM case holds 7.4 grains less powder than does the 7mm WSM, but the 7mm SAUM has proven to be more efficient than Winchester’s short magnum. This means you can almost match the velocities of the 7mm WSM (with the same bullets) using slightly less powder. Using identical powders and the same bullets, Steven Ikeda has found that his 7mm SAUM can match 7mm WSM “book load” velocities with about 7% less powder. In all respects, that’s a good thing. Short Magnums are “overbore” cases with notoriously short barrel lives. Burning less powder should give the 7mm SAUM a barrel-life advantage over the 7mm WSM, and of course, the SAUM costs a bit less to feed. Plus powder charge weight does figure into felt recoil, so a 7mm SAUM will exhibit slightly less recoil than a 7mm WSM running the same bullet at the same speed.

7mm Rem SAUM Load Map
Powder Grains Primer Bullet Velocity Comments
RL 25 62.0 Russian Mag 180gr Berger VLD 2940 Winning load with ES of 7 fps. 62.6 is absolute max, giving 3050 fps in 30″ barrel.
H4831sc 61.0 CCI 250 180gr Berger VLD 2950 You may have to adjust load ? 1 grain to achieve 2950 fps. Low ES/SD.
Norma MRP 61.0 Fed 215 mag 180gr Berger VLD 2986 Load for long-throated chamber, 3.09″ COAL.
RL 25 61.5 Russian Mag 175gr Sierra MK 2980 Works well loaded to mag length. Sub-0.3″ groups at 100.
Win S780 63.7 CCI 250 168gr Sierra MK 2946 Hodgdon Max load, 2.825″ COAL. Powder duplicates factory ammo.
IMR 7828 61.0 CCI 250 162gr Horn SST 2900 Good hunting load with high-BC bullet. 2900 in 24″ bbl.
H4831sc 59.5 Win LR 160gr Nosler Accubond 2840 Consistent, half-MOA hunting load.
RL 15 55.0 Fed 215 mag 120gr Horn V-Max 3260 Great varmint load, 2.800″ COAL. Explosive bullet.
H4350 62.0 Fed 215 mag 120gr Barnes TSX 3310 Hodgdon load, 2.725″ COAL. Low ES/SD.
WARNING: With all loads, ALWAYS START 10% LOW and work up incrementally.
NOTE–These loads are for Remington 7mm SAUM brass. If you neck-down Norma or Nosler 300 SAUM brass, measure your actual case capacity and adjust accordingly.

7mm Rem SAUM — Better Than 7mm WSM?
7mm Remington SAUMFactors Favoring the 7mm SAUM
by Steven Ikeda

Two years ago I decided that some type of 7mm was the ticket for doing well at 1000-yard matches, especially if one could drive the high-BC bullets at 2900+ fps. Looking over various 7mm cartridges that could produce those velocities (and didn’t require case-forming), I was impressed by the 7mm SAUM and the 7mm WSM. According to the load manuals, the 7mm WSM offered a bit more velocity than the 7mm SAUM. However, to achieve its small velocity advantage, the larger 7mm WSM had to burn 7-10% more powder than the 7mm SAUM. (The 7mm WSM has 81.0 grains of capacity vs. 73.6 grains for the 7mm SAUM.) The load manuals also showed that the SAUM would out-perform the 280 Ackley Improved with almost identical charges. As the case capacities of the SAUM and the 280AI are almost identical, that tells me that the SAUM is a very efficient case. It looks like a 6.5×47 Lapua on steroids.

7mm SAUM in a Dual-Purpose Rifle
I’ve built a couple rifles chambered in 7mm SAUM. They have more than met my expectations. My first 7mm SAUM rifle is a Rem M700 built by Greg Tannel in a McMillan A5 stock with a 1:9″ twist, 28″ Krieger barrel. I use it for both long-range tactical matches and F-Class matches (equipped with a forearm sled for F-Class). To my delight, I made the correct choice. I developed a good load for the 180gr Berger VLDs, using 62.3 grains of Reloder 25 and PMC (Russian) mag primers. This load delivered 2940 fps with an ES of 7. That combination of RL25 and Berger 180s won the High Desert Regionals at 29 Palms MCB two years ago. Now after 1600+ rounds down the tube, I’ve also had success with Sierra 175s: 62.5 grains of RL25 and Sierra 175gr MKs loaded to mag length gives me 2980 fps and sub 0.3″ groups.

7mm SAUM Part Deux — New Gun Does Well

Success with the Rem-actioned gun led to my next 7mm SAUM project for Greg Tannel to build. This rifle features a dual-port BAT Model M action in a MasterClass stock. I ordered two 30″ Krieger 9-twist barrels, one for Bench Rest the other for F-Class. Again the SAUM won the High Desert Regionals and got me a second place at the California State Championships. At the 2007 NBRSA 1000-yard Nationals the same load got me first in Heavy Gun High Score.

3050 fps with Berger 180s — and Only 22.75 MOA to 1000 Yards
The 30″ Krieger barrel has produced great velocities. The extra 2″ of barrel increased the velocity (compared to the 28″ tube on my other 7mm SAUM) but it also increased the ES to 11. I guessed that the pressure was dropping off before the bullet got to the end of the barrel so I increased my load to 62.6 grains. That is absolute max in my rifle but hotting up the load did drop ES back down to 6 fps, producing some bughole groups to boot. I’ve achieved 3050 fps with the Berger 180gr VLDs and RL25. I shot that load at Boulder City, Nevada in my F-Class barrel and needed only 22.75 MOA up from my 100-yard zero to get to 1000 yards. [Editor's Note: By contrast, a .308 Win, shooting 175gr SMKs at 2670 fps, will need roughly 34 MOA of "up" elevation at 1000 yards, starting from a 100-yard zero. BIG Difference.]

7mm Rem Short Action UltramagSAUM Brass Options — Rem Works Fine if You Weight-Sort and Neck-Turn
There are three sources for SAUM brass now. Remington, of course, makes 7mm SAUM brass and both Norma and Nosler sell 300 SAUM cases that can be necked down to 7mm. The Rem-brand brass is much less expensive than the alternatives. I have to admit that I haven’t tried either the Norma or Nosler SAUM brass, because the Remington brass is fine, IF you weight-sort and prep it carefully. Yes it takes time to sort and you’ll end up tossing a couple cases per hundred, but the Remington 7mm SAUM brass can produce very satisfactory results.

With Rem-brand 7mm SAUM brass, after full BR prep, I find that each lot splits almost evenly into two weight groups separated by about two (2) grains. I still get a 2% cull rate. The only issue I have is that with the hotter loads, the cases need annealing after 4 or 5 firings. Necks are on average about .001 out of round so I turn them just enough to clean them up. This gives me a loaded round neck thickness of 0.314″.

CONCLUSION — 7mm SAUM Is Fully Competitive with the 7mm WSM
Until something better comes along, I’m sticking with the 7mm SAUM. This case can push the 180s to 3000 fps, and you can’t get to the next velocity node without using a MUCH larger case. Felt recoil is less with the SAUM compared to the WSM. It has better ballistics than the 6.5×284 and the barrel lasts longer also. About the accuracy–people say say that magnums are not supposed to shoot that well. Well, sometimes I have a hard time believing what my 7mm SAUM will do at 100 yards–it has produced some amazingly small groups. The challenge, of course, is duplicating that kind of extreme accuracy during a 1000-yard match.

Great 7mm-08 and 7mm WSM Factory Rifles

Remington’s Model 700 Mountain Rifle LSS (Laminated Stainless Steel) has become a favorite for hunters seeking a versatile, rugged, yet lightweight rifle. With a 22″ sporter-weight barrel, the rifle weighs just 6.5 lbs. without scope. A spin-polished stainless action is mated to a quality laminated stock, that is tough enough for “extreme duty”. As chambered in 7mm-08 Remington, the Mountain Rifle is a great whitetail gun–easy to handle and light on the shoulder during a long stalk. Suggested retail for the 7mm-08 Mountain Rifle LSS is $1040.00, with street price around $750.00.

The stainless A-Bolt, m-1000 Eclipse from Browning offers an ergonomic thumbhole stock, with a smooth action that comes glass-bedded into the stock from the factory. Tipping the scales at nearly 10 lbs., the Eclipse is fairly heavy for a hunting gun, but that weight tames recoil when shooting a heavy caliber. The Eclipse features a 60° bolt-lift, and a 26″ medium-contour stainless barrel, “hand-chambered” according to Browning. This is a nice solid rifle that can do double-duty as a big game gun and a capable long-range varminter. As chambered in 7mm WSM, you can load up 180s for big game, or drive 120s at ultra-high speeds, creating explosive impacts on varmints. MSRP for the stainless m-1000 Eclipse is $1344.00, or $1426.00 with optional BOSS muzzle brake/tuner. Typical retail selling price for a stainless Eclipse is about $1100, based on Gunbroker listings.

The Browning BAR Safari is based on the classic self-loading action by John Moses Browning, America’s greatest arms inventor. This modern version features a multi-lug rotary bolt, engraved receiver, and select high-grade walnut buttstock and forearm. On the front of the barrel is Browning’s patented BOSS system. This is a combination muzzle brake/tuner that really does work. The 7mm WSM BAR Safari with BOSS has a 1:9.5″ twist 23″ barrel, and weighs 8.25 pounds. MSRP is $1237.00 (without scope), but typical retail price, brand new, is $900-$1000.00. You can often find used BAR Safaris for $650.00 or less in superb condition. If you are thinking about a dangerous game rifle, where a fast second shot is critical, the BAR is an excellent choice. There’s also something very satisfying about owning a classic rifle from a legendary gun designer.

Other 7mm and .284 Internet Resources
Reloader’s Nest 7mm-08 Page Over 150 reader-supplied loads for 100-180gr bullets (use with caution).
WikiPedia 7mm-08 Remington Page Cartridge history, dimensions and external ballistics.
Wildcatting the .284 Winchester
by M.L. McPherson
.284 “offspring” 6mm to .375, in Rifle Shooter magazine.
WikiPedia .284 Win Page Cartridge dimensions and external ballistics.
Remington’s Short-Action Ultra-Mags
by Jon R. Sundra
Cartridge history, factory loads, comparison with full-size Ultra-Mags, in Rifle Shooter magazine.
Winchester’s .270 & 7mm Short Magnums
by Dick Metcalf
Cartridge features and factory load performance, in Shooting Times.
7mm WSM Data and Reloading Info Good summary article (with reloading components) from Gunners Den.
Wikipedia WSM Page History of WSM family with basic dimensions.
Short Magnum Cartridges
by Chuck Hawks
Gen’l discussion of cartridge performance.
Reloader’s Nest 7mm SAUM Page Cartridge history and reader-supplied loads for 110-175gr bullets (use with caution).

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