The Suppressor Breakdown

What is a sound suppressor, and how does it work? The first part of this question might seem simple and straightforward - but unless you’re familiar with the science behind it, you might not actually know. Thankfully, you’ve asked the right guy - a man with more suppressors than shotguns. So, let’s take a journey into the world of suppressors to understand exactly how they work, what they are, and what’s under the proverbial hood.

Trick question: They’re the exact same thing. The term silencer was actually a marketing name for some of the first commercially successful suppressors made by Hiram Percy Maxim. If that name sounds familiar, it should. He was the inventor behind the first machine gun, the Maxim gun.

Just for clarity’s sake, sound suppressor is a more accurate term than silencer and one used by the industry as a whole. This is because nothing can fully silence the sound of a gun firing. Even if it were possible to fully suppress the shot itself, you would still have to deal with the mechanical noises of the firearm functioning. But let’s not get ahead of ourselves - we first have to define what a suppressor is and how it works.

Sound suppressors are actually very simple devices that function similarly to a car’s muffler. When a gun is fired, hot expanding gasses travel down the barrel behind the bullet, propelling it downrange. When that hot gas escapes the barrel, we hear it as a loud explosion. This is because the hot gas reaching the relatively cold ambient air creates a shockwave. The other element of a gunshot’s sound is the sonic boom of a supersonic projectile. The latter can be mitigated with subsonic ammunition, but that still leaves the shockwave blast. 

Suppressors work by capturing and slowing some of that hot expanding gas at the muzzle and allowing it to dwell and both cool and expand partially. Depending on the suppressors’ construction, the gas is either dwelling in small chambers separated by baffles or pressed into a latticework of 3D-printed layers.

If this still doesn’t click with you, try this little experiment at home. Take two standard balloons, inflate them as much as you can, and tie them up. Get a sharp object and prick the first balloon. Pop! It’s a loud sound as the pressurized air rapidly leaves the balloon as it structurally fails due to being penetrated. 

For the second balloon, untie the knot at the back and let the air inside gradually leave. It's not very loud at all. The same principle applies to the hot gasses inside a firearm, just with a much louder pop. Now that you understand the basic fundamentals of how the internals of your suppressor work, let’s take a closer look at some of the specifics.

There are two main types of suppressors: integral and external.

• Integral suppressors are built into the gun itself. The most common example of an integrally suppressed firearm is the iconic MP5SD. This design is renowned for its incredibly quiet and for its use by top elite special forces around the world for decades. That said, it’s not the end-all, be-all. And many modern designs offer much better performance for a fraction of the cost of an MP5SD.
• External suppressors are removable devices that mount to the muzzle of a firearm. They accomplish this in one of two ways: either by directly threading to the muzzle, or by attaching to a QD device already attached the muzzle. There are some odd-ball antiquated exemptions to this rule like the Bramit suppressor designed for the Mosin Nagant 91/30 (this simply clipped on to the front sight), but 99.99% of all suppressors made today mount using one of these two methods

A suppressor piston is a metal tube that acts as an interface between the firearm and the suppressor itself. These are normally found on pistol suppressors since they permit the use of a booster or Nielson device. A booster/Nielson device is a short, heavy spring that increases the recoil impulse to allow firearms with a moving barrel to function reliably. For pistol suppressors mounted on fixed barrel PCCs or large pistols like an MP5, shooters should use a spacer to prevent damage to the suppressor.

The front of the suppressor (the part closest to the muzzle) encapsulates the piston head and seals it to the suppressor. The benefit of pistons is that they come in a multitude of thread pitches and interfaces, allowing a shooter to use the same suppressor on multiple firearm hosts. 

One interesting design aspect of some modern pistons is that they are ventilated towards the end to allow some of the initial gas impulse to bleed into the first chamber/baffle of a suppressor.

Baffles are small discs or cones with a hole in the center that allow the bullet to pass through while bleeding some of the gas, propelling the bullet into small chambers between them. Originally, suppressor manufacturers used solid leather discs to accomplish this, with the bullet penetrating the discs with every shot. The issue with this is that the baffles wear out, and since the ATF currently considers those to be regulated components of a suppressor, a shooter would have to send their suppressor back to the manufacturer to replace them. 

This led to manufacturers using aluminum, steel, and titanium baffles depending on the suppressor's caliber and intended use. What’s interesting is that this wasn’t an overnight phenomenon, and many companies came up with unique and cost-effective alternatives before arriving at metallic conical baffles.

• Some suppressors, like the old-school MAC-10’s Sionics suppressor, used packed shoelace eyelets to slow gas before it reached the baffles.
• Advanced models now use 3D-printed titanium structures that resemble metallic sponges—creating an asymmetric matrix of internal chambers.

One interesting minor change to baffle design is the introduction of clipped baffles. If you imagine a small funnel and then cut a hole at the end (or throughout effectively porting the baffle), this is what a clipped baffle is. Sounds like a minor change, but it actually allows much more gas to move from baffle to baffle instead of forward and free from the can. This, in effect, increases gas dwell time and, in turn, reduces the sound signature of the gunshot.

Another style of baffle design is an integral or monocore configuration. This is where the baffles are built into a solid core inside the suppressor that the suppressor body covers. The benefit of these is that they are very easy to clean and never need indexing, and they’re very robust. The downside is that it restricts the internal capacity of the suppressor and can lead to decreased performance. Though we’re talking about imperceivable changes in terms of sound report.

Regardless of how a suppressor’s baffles are constructed, they all accomplish the same task: slowing down the flow of hot gas from the muzzle.

The end cap of a suppressor is simply a threaded or welded circular piece of steel or aluminum with a hole in the center to allow a bullet to pass by. It contains the gasses at the end and, in fully user-serviceable designs, keeps the baffles from escaping the body. But some end caps have secondary functions. For example, in a multi-caliber suppressor, the shooter can often install different bore-diameter end caps to achieve better results. Alternatively, using an oversized end cap reduces the likelihood of a baffle strike / catastrophic failure if you're using a gun with questionable bore concentricity.

Some modern modular designs actually allow a shooter to attach or remove a section of the suppressor body by removing the end cap. These are useful for when a shooter doesn’t need maximum performance but wants a handier, lighter suppressor.

This is a very good summary of the function of a suppressor, but it is by no means all-encompassing. Metallurgy, fluid dynamics, and toolmaking all come in to play when designing a modern suppressor. Writing a complete guide to understand everything that goes into building a suppressor without filling a massive book would be next to impossible.

But this guide excels in giving readers enough information to understand what’s going on in their suppressor and to act as a jumping point to advanced theory and design should they be interested. In simple terms, this guide will give you enough information so you do not sound like a novice when talking shop.