How Do Suppressors Affect Accuracy?
Are sound suppressors useful in competition shooting? In some disciplines, and in venues where sound “moderators” are permitted, the answer is “yes”. In the November 2012 edition of Shooting Sports USA eZine, you’ll find an interesting article about the use of sound suppressors (aka “cans”, “silencers”, or “moderators”). The article explores the use of suppressors in Europe and in tactical matches in North America. You’ll also find an explanation of the rules and regulations governing suppressor ownership and use in the United States.
Shooting Sports Editor Chip Lohman tests three rifles from the bench and found that sound suppressors did not harm accuracy. In fact, all three test rifles (one each in .223 Rem, .308 Win, and .338 Lapua Magnum), shot slightly better 5-shot groups at 200 yards when a suppressor was fitted to the barrel. However, the suppressors did alter point of impact. Interestingly, velocity standard deviation (SD) values were lower with suppressors in place for all three test rifles. This observation calls for further study.*
So the use of suppressors in competition could be a good thing. However, in the United States, current NRA High Power rules prohibit the use of sound suppressors. NRA Rule 3.16.1 subsection (a) states: “Sound Suppressors are not authorized for use in High Power competition.” In addition, there are some practical problems with suppressors — the heat rising off of a naked suppressor can create mirage problems (that’s why some shooters wrap their cans with a cover).
Despite such issues, we are starting to see moderators on rifles used in non-NRA-sanctioned tactical matches. For example, many competitors in the popular Steel Safari field challenge match use suppressors. The photo below shows our friend Zak Smith competing in the Steel Safari with his suppressed Accuracy International rifle.
*The article cautions that one should not extrapolate too much from the SD numbers, given the low number of test shots. Chronograph-maker Ken Oehler, when asked to comment on the SD values stated: “[You should] report the observed SDs, but draw no conclusions until… you can do more testing with larger sample sizes.”