First Round Pop: What It Is and Why We Care
Like any precision mechanical device, suppressors or silencers (the term is interchangeable) have odd quirks unique only to their operation that soon get noticed by their users. In the case of suppressors, many people have noticed a “first round pop” that accompanies firing the first round out of their suppressor during a shooting session.
It isn’t especially loud, nor does it affect accuracy, but since suppressors are supposed to suppress the sound of a gunshot, having a suppressor make a funny noise is eyebrow-raising, to say the least. While we expect babies to suddenly burp and make weird noises, we do not expect that from a suppressor.
So what is a first-round pop? Does it matter? Can it be prevented? Let’s look closer.
Table of Contents
What is First Round Pop, AKA “FRP”?
Suppressors do not operate in a vacuum. When you take them apart for cleaning, all empty spaces in them fill up with the same atmospheric gas we are breathing. That same air around us also will quickly “fill” a suppressor sitting at rest.
So what that means is the inside of your suppressor is filled with gas even before you use it.
When you fire a round, hot, high-pressure muzzle gas blasts inside the suppressor and meets low-pressure gas at the temperature of the environment around you. That gas has to exit the suppressor too, and as it’s suddenly heated, pressurized and pushed out, it makes a popping noise.
In other words, that first-round pop is the purging of the suppressor of low-pressure internal gas. Subsequent rounds do not have that same pop because there isn’t enough time for adequate gas to gather inside to create the pop (unless you wait a long time between shots or take the suppressor apart, at which point, the conditions to create a first-round pop exist again).
How Suppressors Operate
In order to truly understand first-round pop, we have to understand how suppressors work.
Because suppressors are sealed bodies designed to contain, cool and slow the passage of muzzle gas, they are exceptionally good at holding in exhaust and gas, and somewhat poor at venting it off without pressure. This is by design, and something you really need from a suppressor.
A series of baffles or tubes or other flow-constricting devices make up the interior of a suppressor and further ensure that gasses really have to work to get out.
Does a First Round Pop Matter?
In short, no. A first-round pop isn’t a big deal. It will be far more noticeable with slower velocity, small-caliber rounds like rimfire and pistol rounds than with rifle rounds. Let’s just say if you are shooting super quiet subsonic .22 rounds you’ll be far more likely to hear that first-round pop than if you are touching off a .300 Winchester Magnum!
In other words, a first-round pop is only going to be noticeable when you are already pushing the envelope of sound suppression. Remember, a silencer doesn’t create a whisper-quiet, Hollywood myth gunshot. Such shots are possible with some kinds of carefully crafted ammunition or low power rimfire ammo. But the majority of suppressed gunshots will still be audible. They’ll just have the edge taken off them to render them hearing safe without protection.
That means a first-round pop really isn’t a big deal. It isn’t loud enough to hurt your hearing and most likely won’t startle or alert any game animals either. If you are using a silencer on a self-defense gun, again, if you hear a first-round pop it won’t be loud enough to matter. And if you are using a silencer for anything other than self-defense, sport shooting, or hunting, we assume you probably have a government agency to help you deal with that first-round pop.
For people who absolutely can not have that first round pop, there aren’t really many solutions. You might try adding a tiny bit (like less than a teaspoon) of water to the rear of a pistol or rimfire suppressor. This will help reduce the volume of gas present and the vaporized water will help equalize pressure on the first shot.
That said, while that is one of those “neat old tricks” some shooters do, we do NOT recommend it in a rifle suppressor, and you really shouldn’t do it anyway. We only mention it because it always comes up in discussions about first-round pop. The risk of damaging your suppressor, gun, and yourself is too high to justify getting rid of a first-round pop.
Obviously, if you go a long time between shots you’ll create the conditions for a first-round pop again too. It’s impossible to gauge how long between shots will lead to another first-round pop, as the conditions are unique to the time of shooting.
Embracing First-Round Pop
A first-round pop is a simple matter of physics in action. It cannot be helped, and cannot really be prevented. And it really doesn’t matter. For rifle shooters, you’ll probably never notice it over the sound of your rifle, and for pistol and rimfire shooters, it’s a simple fact of life that doesn’t impact hearing safety, accuracy, or ability to hunt.
First-round pops are a well-established phenomenon that mostly impact low-velocity, low-pressure shooters. Think of it as the equivalent of a fouling shot for suppressed guns. It’s just going to happen, and it’s just going to be unique to that first shot fired. Get that first round pop, and then forget about it.
If you’d like to experience your own first-round pop, we sell silencers in all 42 states where silencer ownership is legal. Check out our incredible selection and learn how you can legally purchase and register a silencer from the comfort of your own home. Then take a look at our incredible selection of the best silencers on the market, including the all-titanium, multi-caliber BANISH line of modular suppressors.SHOP SILENCERS