Posted on: 2011-04-17 21:32:00 -0400
I took my new AAC SPR/M4 for a spin on my precision AR-15. It drastically reduces muzzle blast, but there’s still plenty of noise coming back through the ejection port along with the supersonic crack of the bullet. It doesn't feel entirely comfortable to shoot without hearing protection. Even so, it was fun to do so a number of times and clearly hear the bullet impact the berm or steel target.
The SPR/M4 can attach to the rifle in five different positions. All of them produced some amount of zero shift, varying from .2 mil up and .1 mil left to .7 mil right and .3 mil down. I’ll check the repeatability of the zero shift during my next range trip. The rifle grouped at least as well suppressed as unsuppressed. The suppressor attaches securely but does have a slight amount of play.
Much of the suppressor’s noise reduction comes from turning muzzle blast into heat. Hence, it heats up fairly quickly and starts creating noticeable mirage in the scope after 15–20 rounds. I brought along a hand towel and wetted it down to cool the suppressor. The long-term solution will be to order a TAB suppressor cover.
The suppressor also produces a fair amount of back pressure that blows gas back through the charging handle and into the shooter’s face. This was slightly disconcerting at first but not that big a deal. I still see myself getting a PRI gas buster charging handle to divert the blowback off to the side.
It would be interesting to try the suppressor on a bolt-action rifle, as this would eliminate any ejection port noise and gas blowback.