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.
A couple things to note here, but first a caveat: I don’t know the exact answer for how much dB reduction before you see serious degradation in energy but I’ll answer some of the other questions you mentioned.
I wouldn’t say 14” is common, any rifle barrel shorter than 16” is illegal without extra paperwork and a tax stamp and all that (classified as a short barreled rifle). In addition to this, ballistically speaking 16” is a sweet spot for 5.56/.223 so it’s all the more common on top of the legality.
The other thing is that (generally speaking) a suppressor is really just a hollow can with a bunch of angled walls (baffles) to disrupt the airflow, allowing it more time to cool before exiting. Bigger differences in temp/pressure = louder bang, a suppressor reduces this big differential by delaying the exposure, buying time for the gas to expand and cool in a controlled manner as it exits.
So really the longer the suppressor, the more baffles, etc., you will get more dB reduction but you’re also going to start running into problems cycling the rifle. Since you said AR/5.56, you would get to a point where the rifle just doesn’t fully cycle, the bolt doesn’t go all the way back failing to strip another round from the magazine, resulting in a single-shot rifle (shoot, pull charging handle, repeat)
This is a common problem with suppressors and why most suppressor hosts like to have an adjustable gas block for this type of thing.
Yes, use-cases are important. Suppressors can be used to mitigate multiple signatures like flash and sound, and while length feeds into that, where it’s going to be used matters as well. Tight quarters inside a building vs outside at range, things like that all feed into the right “kit” for the “mission” (but then we get into caliber and grain count discussions)
When you are looking for a suppressor for a rifle, you need to consider the obvious stuff like the caliber and whatnot, but also you need to consider the things like flash hider/suppressor host and the gas settings of the gun, what the buffer weight is in the buffer tube, etc.
For example, a mk18 is considered a very gassy gun, when you slap an SF RC2 or KAC QDSSNT4 on that thing, every pull of the trigger will be spewing a lot of gas in your face from the ejection port and charging handle areas. So is the mk18 a bad gun? No (lmao) it’s a CQB rifle with a short barrel which means less dwell time for the projectile as it is leaving the barrel which means more chance of unburned powder, etc. - I’m hoping you get the picture. It’s a rifle for close-in fighting so you don’t want a long ass suppressor or get gassed out but you DO want to be suppressed indoors.
So what do we do about it? Well suppressors are not all made the same way and relatively recently we’ve been seeing an influx of 3D printed suppressors like the Flow-through cans and they have been a game changer.
Here’s one of the most popular/trusted ones: https://huxwrx.com/flow-556k-suppressor
One last thing to note, you mentioned diminishing returns on length/weight, you’re right to think that. As I mentioned length is beneficial for things like dwell time and giving time for the gasses to cool some before exiting but you also have to consider things like a long suppressor starting to sag over time which leads to baffle strikes which will destroy the can.
Ultimately it’s all about the use-case. Every can and can-host has its own quirks, dB level, etc.
HUXWRX sounds like an Amazon brand