A common misconception is that suppressors are only useful if they “silence” the shot of a cartridge being fired. This is not entirely true. While the intention is often to make the weapon as quiet as possible, in military applications it is just as important to disguise it.
When a round is fired and the very hot high-pressure gases exit the barrel quickly, they make the distinctive gunshot sound. When a suppressor is attached to the muzzle it gives the gases a place to expand and lose pressure, and in many designs to cool significantly and lose even more pressure, so when the gas exits it makes much less sound. The amount and nature of this sound will vary with silencer designs–from being dramatically reduced, to essentially inaudible. Some designs patented have endeavored not to reduce the amount of sound, but to raise its pitch above the humanly audible frequencies. Even moderately efficient designs that do little to contain the sound, will usually disguise it enough to have value in preventing the “shootee” from accurately determining the direction from which the shot came, thereby delaying or preventing return fire.
While some come relatively close (especially in smaller calibers), no suppressor can completely eliminate the sound of firing a firearm. Supersonic bullets produce a miniature sonic boom, resulting in “ballistic crack,” and even bullets traveling below the speed of sound make distinct noise by their passage through the air and impact on target. Firearms themselves are prone to mechanical noise, especially semi-automatics that have to bleed off some of the gases to cycle their actions.
Forms Follow Function
A suppressor itself is typically a hollow cylinder or tube, commonly steel, stainless alloy, titanium or aluminum, containing a series of expansion chambers, which attaches to the muzzle of a firearm. Suppressors reduce noise by allowing the rapidly expanding gases from the firing of the cartridge to be briefly diverted, delayed, or trapped inside a series of hollow chambers. The trapped gas expands and cools as it interacts with the chambers, and its pressure and velocity is decreased before it exits the suppressor. The chambers are usually divided by baffles. The number of chambers varies widely by design and range from a couple to more than a dozen depending on the intended caliber, use, and design details.
Often, a single, larger expansion chamber is located at the muzzle end of a can-type suppressor, which allows the propellant gas to expand considerably and slow down before it encounters the baffles or wipes section of the suppressor, the first of which is usually referred to as the “blast baffle.” Effective suppressors either use a large total suppressor volume or a moderately large volume plus many baffles. Many suppressor designs trade reduced total volume and weight for somewhat louder noise, which is still of significant tactical advantage. The optimum compromise for any particular design depends on the suppressor’s intended use.
The Leading Edge
Considered to be on the cutting edge and well known in the industry, the Gemtech G5 is widely used by federal agencies, military units, and civilian shooters. It is designed to work with any 5.56mm NATO (.223 Remington) firearm that is threaded at the muzzle (1/2×28) and has the 1/8-inch or so of clearance that allows for the push-twist movement of the locking mechanism. The can is constructed entirely of titanium, stainless steels and Inconel (Inconel is an oxidation and corrosion resistant nickel bronze extremely well suited for service in extreme environments) to give it maximum durability and long-term performance. Suppressors typically use a series of stacked baffles that are press-fit together and then secured inside the body by threaded end caps that are then tack-welded or pinned in place. Some manufacturers use a welded core that doesn’t allow for the replacement of the baffles in the event of a baffle strike or at the end of their service life. For military units this is not as big a deal, but for law enforcement agencies and qualified civilians, this could mean the difference between a warranty claim and having to shell out for a new suppressor.
In many varieties, the can is pulled back against the tension of a large captive spring, turned about a quarter-turn and released; the suppressor is now attached and ready to fire. To remove it the process is simply reversed. I have found that during extended firing sessions on short-barrel rifles, a suppressor can be difficult to remove due to the build-up of carbon fouling. This is not unusual for any type of suppressor using a quick-detach-style flash hider, but is something the shooter should be prepared to deal with. Modern suppressors either thread onto bare muzzle threads, or they mount over a flash hider. The King silencer tested by the U.S. Army circa World War I fit over the muzzle and attached to the bayonet stud on a Springfield M1903 service rifle. Prior to the 1934 Firearms Act, .22-caliber rifles were marketed with the silencing expansion chambers built into the rifle barrel, such as the Remington “Gallery Rifle.”
The finish of many suppressors is a beautiful black oxide that is very flat and non-reflective. There have been no issues with the specimen I tested, over thousands of rounds fired, and it has held up well to the extreme heat and varying environmental conditions I have put it through. It is worthwhile to note that nearly all of the “paint” style finishes will burn off under heavy use and the can that looked so nice on the dealer’s shelf will begin to look like an old barbeque grill after the first heavy use.
I have seen no discernable change in point-of-aim/point-of-impact with the suppressor in place and accuracy actually seems to improve slightly. A call to the manufacturer verified these observations. It was explained to me that the effects of the suppressor to quiet the hot, rapidly expanding gases also removes erratic disturbances from the gases as it pushes the bullet out of the bore thereby resulting in faster stabilization as it heads towards its target. While I didn’t do any chronographic testing, I was also told that I could expect a small increase in velocity referred to as “freebore boost.” This is basically the bullet getting a little extra nudge as it passes through the suppressor. Reliability of the host firearm has been unaffected.
I am not one to put a lot of stock in published numbers off a chronograph or decibel meter. They are too easily skewed to show favorable results. Even from a short-barreled carbine (10.5-inch Mk 18) the muzzle blast and recoil are completely eliminated and the report diminished to about that of an unsuppressed .22 LR rifle. Standing away from the shooter, the sound generated from the shot is even less noticeable and the most prominent sound becomes the swishing crack of the supersonic bullet as it goes downrange. The late Col. Townsend Whelen recalled once testing a Maxim silencer on a Springfield rifle, firing down a railroad right of way: as the bullet passed each telegraph pole it returned the echo of its sonic crack to the shooter, sounding as if one had fired a burst from a machine gun.
I have been extremely impressed with the latest suppressor. Add the fact that it is seeing daily use by military units such as the 101st and 82nd Airborne Divisions in the War on Terror and you have a very impressive accessory indeed. It is quite a testament to the quality of today’s suppressors to have them enduring the rigors of daily combat use.
A common misconception is that suppressors are only useful if they “silence” the shot…
by R. Lee Ermey / Jul 1, 2008