Totally off the wall question, which I realize probably isn’t very meaningful, but I was watching a movie where a character was using a suppressed rifle. Looked like an AR/.223 (I assume).
Well it got me thinking - how much can a given gun be suppressed (decibel reduction) before performance is significantly reduced (I assume it must impact performance, even if just a little since it’s attenuating sound waves, which are energy, but what do I know?).
I’m sure it varies by round/load, barrel length, etc, so let’s assume a subsonic .223 round in a 14" barrel (is that a common lenth?). Or if you know a specific case that’s fine too.
Surely there are reasons why a given suppressor is chosen for a specific use case, and I don’t know enough to see that (diminishing returns for length/weight?)
I tried asking chatgpt, but it just returned generic suppressor info.
Suppressors generally improve ballistic performance, the tradeoffs are in other areas (weight at the front of the gun making it hard to handle, reduced lifespan of parts due to increased backpressure, and that backpressure also often blasts the operator with a faceful of toxic gasses that increase your risk of cancer)
Suppressors tend to function (in terms of ballistic performance) as a longer barrel, increasing the distance over which expanding gasses can increase the velocity of the bullet before the propelling high pressure gasses can equalize into the atmosphere, and longer barrels do eventually decrease balistic performance, but that’s not generally relevant to the actual barrel lengths people use. No idea how long you’d have to make a barrel to decrease performance, or how that might translate to how long a suppressor would need to be to decrease performance
Level of sound suppression is also usually a function of volume and the suppressor’s design, but volume isn’t the same as length, so that also complicates things
I don’t think the question you asked can really have an actual answer, but hopefully this response and others kinda paint a picture of the kinda stuff you’re generally hoping to learn from this thread :)
Short answer, about 30db give or take a little. My rifles run in the 130db unsuppressed and in the 90db’s suppressed
Also, utterly ignoring the noise question, the AR platform has been adapted for almost every caliber. There are straight-wall caliber ARs. I haven’t yet seen one in .50 cal, but I wouldn’t be surprised if someone showed me one.
Point is, you can never guess the caliber of an AR unless you’re looking at old war footage.
I’ve heard that the MP5SD (or whatever the actual model is; the MP5 with the built in suppressor) is so quiet, all you really hear is the hammer clicking.
The SF variant of the H&K USP actually has a locking bar to hold the slide closed. Or at least that was one of the production runs, they may have dropped that feature. The intention there is that you want something that’s so quiet that even the slide racking is too much noise. You’d run it with a suppressor and subsonic ammunition.
Effectively it turns it into a manually operated pistol, allowing the user to choose when they chamber the next round.
There are ways to stop any gas from escaping the barrel, meaning complete silencing of that noise. For example, captive piston ammo, which I bet someone has developed into a captive piston suppressor to let the bullet accelerate longer.
Mechanical and bullet flying noises will remain.