Free Shipping:

All orders from Silencer Shop ship free!

What is First Round Pop?

Most people who start looking at suppressors, come across the term First Round Pop (also known as FRP) pretty quickly. At a very basic level, the term First Round Pop is referring to the first round that's fired through a suppressor after it's been out of use.  Since the suppressor is initially filled with oxygen, there will be an additional 'pop' as the oxygen burns out - which makes the first shot louder than subsequent shots. FRP3 Depending on the suppressor, firearm, ammunition, and environment; the FRP can range from almost non-existent to very noticeable.  Unfortunately, because of all the variables involved, it's extremely hard to get consistent FRP measurements. Keep in mind that, although FRP can be noticeable, the suppressed shot will be just slightly louder than subsequent rounds - so it's not something to be overly concerned about when it comes to either overall enjoyment or hearing safety. Having said that, there are several factors that tend to impact FRP fairly consistently:

Caliber

Although FRP is definitely present on higher pressure calibers, it's not as noticeable because the rounds are so much louder. As a result, you'll hear a lot of talk about it when referring to rimfire or pistol suppressors - but nobody really cares on a suppressed .338 Lapua. :)

Monocore Suppressors

Some suppressors are designed with a core that comes out as a single piece: like the SilencerCo Sparrow SS.  Those single-piece designs are typically referred to as Monocore Suppressors. As a general rule, a monocore suppressor will have a louder FRP than a suppressor that uses individually stacked baffles.  Some examples of individual baffle designs include the Tactial Solutions Axiom or the Griffin Revolution 9.

Bore Size

It's very common to use a larger bore suppressor for use with multiple calibers. For example: a .45 pistol suppressor works great for suppressing a 9mm or .40 handgun; or, a 7.62mm suppressor will come very close to the performance of a 5.56mm suppressor. Unfortunately, there are always trade-offs - and one of them is you'll generally have a noticeably louder first round pop when shooting sub-calibers through a larger bore suppressor.

Time Since the Last Shot

After hearing about FRP, one of the first questions we get asked is how long a suppressor can sit unused before FRP will occur again? This is hard to answer because it's extremely dependent on the environment.  For example, on a windy day at the range you'll get that First Round Pop more often than you would shooting at an indoor range.

Working Around FRP

In most cases, First Round Pop probably isn't enough of an issue to worry about; since, aside from just sounding louder, it doesn't cause any issues. Having said that, if it's bugging you and you want to reduce it as much as possible, try adding just a teaspoon of water to the rear of your rimfire or pistol suppressor before shooting. I would NOT, however, recommend adding water to a rifle suppressor in most cases.

Conclusion

At the end of the day, First Round Pop can definitely be noticeable on low-pressure calibers (like pistol & rimfire); but, it's not that big of a deal for most users. Personally, I'd suggest using FRP as a tie-breaker if you have 2 suppressors you're interested in; but, I probably wouldn't consider it as a primary requirement in most cases...  

3 responses to “What is First Round Pop?”

  1. George S Young says:

    I have a variety of rimfire, pistol and rifle suppressors. Some units are over 30 years old and are from Automatic Weapons Company – AWC and still hold up with some of the most “modern” designs at the range when standing 15 – 20 feet away they all sound about the same in their respective calibers…
    Anyway, I have both baffle stack and monocore .22 cal suppressors of varying lengths from several companies. I never have a problem with first round pop. I always put a little bit of either plain lithium or full synthetic grease in the rear blast chamber – it really lowers the whole tonal spectrum of the noise from the suppressor, it is a much more pleasing, softer sound. Additionally, to truly reduce first round pop I spray a liberal amount… two seconds or so of Rem-Oil down the exit hole of the suppressor, you can tip it down to drain any excess or just shoot it… any excess will be blown out with the first shot or two. I guess this is what most people think of as shooting wet but the advantage of spraying Rem-Oil down the suppressor is that it totally displaces the oxygen that causes the first round pop and of course lowers the dbs of the shooting experience for up to three magazines full. Monocore or baffles no longer matter to me although I prefer baffles due to their inherent nature to simply have almost no first round pop when shot dry. I would guess that all that baffle space simply takes up so much space that there is not much air in the can to begin with, but I really do not know that for a fact. I’m fascinated by take apart suppressors and have a habit of taking mine apart regularly and cleaning them way before the recommended time… simply makes the cleaning so much easier. And since I have been using a product called Seal 1 the carbon and dirt literally just wipe off the baffles or monocore… the hard carbon is just not there. Using fully synthetic NAPA 0w-20 comes close to doing the same thing. If you buy Seal 1 try the paste on your baffles or monocore… you will be amazed. Thanks to Jake Owens over at AWC for turning me on to this all natural, non hazmat and shippable through the US Mail, except for the aerosol version which goes on to thin for me for suppressor use but is an excellent gun lubricant and so far has worked at -15 below zero F this year. It will get colder this winter and I’ll keep yo informed…
    George S

  2. Rob Rice says:

    I’ve read about the RemOil and I wonder if it’s the oil or mostly the propellant, which replaces oxygen with an inert gas? Some recommend “gas duster”, a spray can used to clean keyboards or lenses. Some aerosol cans use fluorocarbon as a propellant, but some use propane. It’s probably important to establish which before trying different sprays!

Leave a Reply

Your email address will not be published. Required fields are marked *