I read a thread on a gun forum the other day. Someone with a lot of science knowledge, but no practical firearms experience, was arguing that a silencer was useless on a gun that fired a supersonic bullet. He was “enthusiastic” with his argument that you can’t do anything about the sonic boom of an object traveling faster than the speed of sound, or more 1,125 feet per second or so depending on environmental conditions. His premise was flawed, however, by his lack of understanding that the sound of a gunshot has three components. Those are the blast of the rapidly expanding gas exiting the muzzle, the sound of the action of the gun, and the sonic boom of the bullet when firing supersonic calibers. His argument completely missed the point of all the benefits of reducing the gas expansion noise. That’s what has the most impact to the shooter. He also missed the potential benefit of a suppressor masking the location of the shot in supersonic scenarios. While the sonic crack still happens, it’s difficult to figure out where it came from without the associated muzzle blast. That’s useful for law enforcement, military, and hunters.
With all that said, the bottom line is that suppressors for a supersonic round like .223 Remington are a great idea. They’re loud! In fact, a 55-grain .223 Remington fired from a 16” barrel will come in at about 164 decibels, depending on muzzle device configuration and such. That’s way louder than the takeoff noise of a jumbo jet (150dB) and well above the threshold for permanent hearing damage. Adding a suppressor will knock that noise level down into the 130’s depending on make and model.
All this is a long way of saying that adding a silencer to an AR-15 is a great idea. With this in mind, I decided to test the GemTech G5-T 5.56mm suppressor. Thanks to our friends at SilencerShop, I was able to borrow one for a bit.
The G5 series comes in two models: the standard G5 is made from stainless steel, Inconel and titanium and the G5-T has a body constructed entirely of titanium. The blast baffle on the G5-T is made from Inconel for durability and erosion resistance. Both suppressors have the same exterior dimensions with a length of 7-inches and diameter of 1.5-inches. The titanium model is noticeably lighter at 14.3 ounces while the steel model weighs 18.8 ounces. The other primary difference between the two is that the regular G5 is coated with matte black Cerakote, which offers a reduced heat IR signature. If you’re planning on sneaking around and trying to avoid people with thermal vision optics, this model might be your huckleberry. Gemtech claims that both models offer a 32 decibel sound reduction.
The 5.56MM Quickmount for G5 and G5-T is simple to use and offers a repeatable mounting method. This means that if you remove and re-mount the suppressor, there won’t be any additional changes in point of impact.
Here’s how it works. The G5-T ships with a G5 Quickmount flash hider. The device does not have to be timed or oriented in a certain way. This makes life easier as you don’t have to use any spacing washers to get it tight and oriented correctly. When you remove your existing muzzle device, be sure to remove the crush washer too if that’s present. You should mount the G5 Quickmount directly to the barrel with no other washers in place. Make sure you clean the threads, and you might want to apply a couple of drops of Rocksett to keep the muzzle device in place. You’ll want to torque the flash hider to the barrel with 35-45 foot-pounds of force.
The Quickmount has two lugs of different size that mate with two holes in the suppressor body. Simply press the suppressor onto the mount (it will only go on one way) and push hard enough to overcome the spring inside the suppressor body. Now rotate 90 degrees and make sure the spring pulls the suppressor back away from the muzzle. To remove, pull the suppressor towards the rifle, rotate 90 degrees in the opposite direction, and it will slide right off. It’s a simple system, and I had no trouble getting the suppressor on and off during range outings after it got hot and dirty.
GemTech makes a slew of Quickmount devices with different thread patterns. Right now, you can order the following:
- 1/2-28 Standard (Fits barrels longer than 11”)
- 9/16-24 LH (FNC, FS2000)
- 9/16-24 RH (Ruger AC556, Mini-14)
- M12x1mm LH (FN P90)
- M13x1mm LH (Steyr AUG)
- M13x1mm RH (Galil)
- M15x1mm RH (HK93)
- M18x1mm RH (Sako, Tikka)
- 1/2-28 Extended (MK-18 with 10.3” or 10.5” barrel)
I shot this suppressor from two different rifles, a DPMS Lite 16 A3 AR-15 and an FN-15 DMR (Designated Marksman Rifle.) On both rifles, the blowback was minimal. I felt a little breeze on the side of my face, but none of the normal powder blast.
I wanted to check for accuracy and point of impact shift, so I used the FN-15 DMR and shot 5-five-round groups at 100 yards with and without the suppressor mounted. I used Federal’s American Eagle AE223 .223 Remington ammunition. This is a standard 55-grain load that I’ve found to be surprisingly accurate. It’s a great value for volume shooting.
I fired a couple of groups unsuppressed with the DMR and measured five-shot spreads at 1.79 and 1.78 inches. After adding the G5-T, those groups shrank to 1.22 and 1.43. Technically, silencers aren’t supposed to make a rifle more mechanically accurate, but I almost always get better groups using one. Less blast and recoil makes it easier to shoot better.
I also measured for point of impact shift. Adding a suppressor will almost always cause a change to the point of impact of rounds whenever it’s mounted. For the G5-T, the groups were exactly 2.75 inches lower and dead center laterally when compared to the unsuppressed groups. I removed and re-mounted the suppressor, and there was no change. That’s exactly how it’s supposed to work.
GemTech Suppressor Bolt Carrier
While I was at it, I also checked out the GemTech Suppressed Bolt Carrier. Adding a suppressor completely changes the gas dynamics of an AR-15, so the idea with this product is to offer two modes of operation for suppressed and unsuppressed fire.
Here’s how it works. There is an adjustable gas valve in the bolt carrier itself, just past the bolt carrier key channel. Using a flathead screwdriver, you twist the valve 180 degrees to choose between the unsuppressed and suppressed setting.
I tried this in the DPMS Lite AR-15 to see how it worked. The kit contains the bolt carrier only, so you remove your existing bolt and carrier and move the firing pin, cotter pin, and bolt to the new carrier. Easy enough. The function was just fine, and I noticed no hiccups of any kind. Just for kicks and to be a rule breaker, I even ran it for a while in the unsuppressed setting while the GemTech G5-T was installed. I figured this would be pretty much the same as using a standard bolt with a suppressor. Operation felt about the same to me. 5.56mm AR rifles don’t generally create a lot of facial blast like other guns do, so I didn’t perceive a dramatic difference. Yes, I felt a little less of a suppressor breeze on my face, but as it’s not a big deal to start with, I can’t say the effect was life changing.
To understand the difference in bolt carrier speed, you need some pretty high tech equipment. The folks at GemTech did exactly that and captured operation using a 5,000 frame per second high-speed video camera. That allowed them to calculate bolt speeds with normal bolts, the GemTech carrier in the unsuppressed setting and the GemTech carrier in the suppressed setting. You can read the full report here.
The Cliff notes are that use of the carrier will reduce bolt carrier velocity significantly. According to GemTech’s tests, there was a 25% decrease in carrier velocity when firing a 14.5-inch Colt M4 and a 16% reduction with a 10.5-inch Daniel Defense MK18.