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Can You Suppress Supersonic Ammo?

When people first start learning about suppressors, one of the first 'facts' they learn is typically that you can't suppress supersonic ammunition. This couldn't be further from the truth!

What is the Supersonic Crack?

After a bullet is fired, it creates pressure waves as air is displaced along its path.  Essentially, the air has to move out of the way so rapidly that it's forced to be temporarily compressed. Suppressing Supersonic AmmoWhile this pressure wave is created at any speed, it becomes noticeable as a 'crack' once the bullet surpasses the speed of sound (which is approximately 1125 feet per second).  At that speed, the pressure waves can't get out of the way fast enough - and they merge together as a 'crack' that travels away from the bullet at the speed of sound. Unlike the report of the firearm, which has a very specific origination point, the supersonic crack actually originates along the entire path of the bullet - as long as it's traveling faster than the speed of sound. Because the supersonic crack is traveling with the bullet, it can't be localized the same way a typical gun shot can.  Many hog hunters will point out that; although the hogs can definitely hear the crack, they don't know where to run when using a suppressor.

How loud is the Supersonic Crack?

There are lots of factors that impact how loud the supersonic crack is; but, in most of our testing we've found it isn't very loud compared to the report of the firearm. When shooting a suppressed .22, for example, the difference between subsonic and supersonic ammunition is typically only a couple of decibels.  There's actually a bigger difference when going from a low-end to a high-end model.  (We did this testing with a .22 because it's easy to get ammo that runs just under or over the speed of sound - so we could eliminate other variables.) Having said that, the decibel level doesn't tell the whole story for a couple of reasons:
  1. The supersonic crack is a sharp sound that's typically less comfortable than the 'thud' of a suppressed round.  As a result, it often sounds like it's louder than it really is - which has a real impact on whether the shooter feels like they need additional hearing protection.
  2. Every shooter has a different comfort level when it comes to sound; and, if you're already close to you maximum level the supersonic crack will probably push you over it.
In other words, even though it isn't that loud in the grand scheme of things, the supersonic crack can make a real difference to how much you enjoy shooting.

Why is it a Bad Idea to Always Shoot Subsonic Ammo?

While it's true that shooting subsonic ammunition is going to be quieter, it isn't always a good idea for a variety of reasons:
  1. With semi-automatic rifles, such as the AR-15, they typically won't operate correctly unless they have enough blowback.  Subsonic ammunition just doesn't have enough pressure to make the rifle run correctly.
  2. Most barrels are designed with twist rates that are optimized for a specific caliber of bullet travelling at a standard velocity for that caliber.  When using subsonic ammunition, the bullet is going far slower - and often won't be stabilized correctly.  This has a real impact on accuracy, even at shorter distances.
  3. Aside from the loss of accuracy, you'll also lose significant range simply because the bullet is traveling slower.
  4. For hunting or home defense applications, most people prefer to use high-power ammunition that's specifically suited to their purpose.  When using a suppressor, you should still use your preferred ammunition so you don't get substandard results - and you'll still be protecting your hearing & situational awareness in the process.

Can Supersonic Ammunition be Suppressed?

Absolutely, yes!  Some of the most enjoyable rounds to shoot suppressed are supersonic. In those cases, the supersonic crack is still far below the 'comfort threshold' - so it's possible to enjoy hunting or shooting without hearing protection. For example, shooting a full-power .270 or .308 is completely comfortable for most people when using a bolt action rifle.  It's amazing how quiet a good suppressor really is!  Even high-power rounds like .338 Lapua become extremely comfortable to shoot with a good suppressor. On top of that, you'll see reduced recoil, better accuracy, and increased velocity/range when using a suppressor - so there isn't much downside. On the other hand, there are some weapons that ride the line of what's comfortable - like a 9mm pistol.  In those cases, a supersonic round is still hearing safe for home defense scenarios - but it's just a little to loud to be comfortable for most people at the range.  Subsonic 9mm ammo, on the other hand, sounds significantly better because that sharp crack is eliminated. Another thing I, personally, recommend is to try a suppressed .22 with supersonic ammunition.  It's completely comfortable; and, in the right conditions the echo of the supersonic crack will make it sound like you're being shot at since you won't hear the report of the gun you're firing.  I've seen multiple people put the rifle down, thinking something was broken - and it's actually kind of funny.

Conclusion

At the end of the day, using  a suppressor will benefit pretty much any firearm. When you get your first silencer, don't feel like you can only shoot with subsonic ammo (unless the model is only rated for that).  Be sure to at least try it with supersonic ammunition, and I suspect you'll be impressed with the results!  

8 responses to “Can You Suppress Supersonic Ammo?”

  1. Greg says:

    Great article! I’ve been using Beck Ammunition (formerly Right 2 Bear Ammo) 150 grain pointed soft point for pig hunting. It’s comfortable to shoot, ballistics are really close to .30-30, and is plenty quiet out of a 9″ SBR with an AAC 762-SDN-6.

    Don’t know if it’s true or not, but I’ve also heard that shooting supers through a sealed suppressor (not user serviceable) every once in a while helps to keep it cleaner longer.

    • jeremy@silencershop.com says:

      Good to know on the ammo. Rifle silencers don’t have to be cleaned since all that gets in there is carbon. However some people shoot cast lead or 22 through there sealed silencers and that can cause some build up. Griffin Armament just recently came out with two silencers for centerfire rifle that can be taken apart and cleaned very easily for people that want to have more flexibility with their rifle silencer.

  2. Terry Copple says:

    Soldiers were irritated when they ran out of subsonic rounds for their M-16s with Sionics suppressors. Something about the supersonic shriek of the bullet on the way to the NVA soldier attracting attention.

  3. evlutionz LLC says:

    Excellent article. This confirmed a few things I have experienced but hadn’t heard anyone else discuss.

    To be noted, environment can have a lot to do with shooting comfort/experience while firing supersonic rounds suppressed. For example, firing in an indoor range or near a wall, dense bushes, vehicle, etc. can still seem somewhat loud or very loud while firing that same weapon with the same ammo in a wide open area can seem drastically quieter and comfort is not an issue. Users should do their own testing and experimentation with environment, weapon platform, and ammo to be able to identify when and where they may want to employ worn hearing protection as an effort to not get their bell rung. Sometimes the sound of the projectile striking a backstop, etc. can be a factor as well. Regardless, shooting suppressed with a well designed suppressor is generally much more comfortable than taking the full audible brunt of the muzzle blast. Stay quiet….

  4. JoeW says:

    I shoot handloaded subs along with supersonics through my .308. The subs are crazy-quiet – racking the rifle is louder than the round going off. I was out in the desert at one point, shooting supersonics toward a mountain, and it sounded like someone was shooting back at me. The rifle would go “pfffft” and a second later you’d hear a “crack” bounce back off the mountain …. either that, or someone WAS shooting at me {:-{

  5. Lodewyk says:

    I love my Sig SRD 7.62Ti QD! I shoot sub-sonic 300BLk and it sounds like a suppressed 22lr. However that same can is great with supersonic ammo as well including on my .308 POF, and my 30-06 Tikka hunting rifle – the supersonic crack is not that bad and it is a pleasure to shoot those loud rifles suppressed. Now the bolt and spring in the AR-10 is annoying – because I can hear it!. Now waiting for the Sig SRD 338Ti QD for my Lapua! I bet that will be fun to shoot because that is one loud rifle!
    I only use supersonic 22LR ammo and they are super quiet and can hear the impact on the berm rather than the supersonic crack. An unsuppressed 22lr pistol is much much loader than a suppressed 45acp or even a 9mm. So if you want to preserve your hearing – buy cans and lets get the laws changed. Cans should be considered accessories, not NFA items!!!

  6. Charlie says:

    I have a 70 yd range off of my house porch. when I back up to keep the westerly sun off of me the bounce back of the blast is quite a bit louder bouncing off the house wall, but I still like the suppressor because my neighbor has several horses just over the fence about 50 yds away. the horses usually just look my way after the first shot. my hearing has got to the point just one unprotected shot from any centerfire and 22 mag hurts my hearing. I have hearing aids but they are painful to wear so they are wasted money. I could have bought several more suppressors for what the aids cost. I have a lot tied up in suppressor adapters and barrel threading but it is worth it. maybe trump will help us out on the hpa. If a person was to only use suppressors when he shoots the cost and quality of life experience would far exceed the cost of the suppressors if he didn’t need hearing aids later in life. You will understand if you shoot a lot even a 22lr will have a detrimental effect later in life.

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