What determines suppressor perceived db ?

[DLT]

Probably an easy question for many on here but I have not owned a suppressor long at all and have only shot mine on a 16” 6.5 grendel a.r. platform. It’s a huge noise reduction don’t get me wrong but it still catches me off guard with how loud it actually is. Today I shot it on my 26” 6xc bolt gun and it feels like it’s half as loud even though it’s going 500fps faster than the Grendel, it’s absolutely a pleasure to shoot even with out ear protection. My cousin has a “supposedly” better suppressor he shoots on his 22” .243 and it’s loud as crap to me too. Is it the extra barrel length why it seems so much more quieter than my grendel and his .243 ? A 6xc and .243 win is very close in speed and powder cap.

 

[ELR LVR]

Yes

 

[dellet]

Barrel length is part of it. Longer the barrel the less muzzle pressure and blast to mitigate. But you would need to stand in front of the muzzle to really hear that difference.

The noise you are hearing with the AR is actually coming out the ejection port. If you can shut off your gas, you could compare barrel lengths only.

A couple ways to lessen the noise in a semi auto is to increase the unlocking time of the bolt, slow the actual speed of the bolt, lengthen the gas system or tube.

Different powders also have different sound signatures. So using two different powders even in the same cartridge and rifle can be completely different.

Lots of variables

 

[ELR LVR]

Barrel length is part of it. Longer the barrel the less muzzle pressure and blast to mitigate. But you would need to stand in front of the muzzle to really hear that difference.

The noise you are hearing with the AR is actually coming out the ejection port. If you can shut off your gas, you could compare barrel lengths only.

A couple ways to lessen the noise in a semi auto is to increase the unlocking time of the bolt, slow the actual speed of the bolt, lengthen the gas system or tube.

Different powders also have different sound signatures. So using two different powders even in the same cartridge and rifle can be completely different.

Lots of variables

Thats a very good point regarding 2 different powders
I know when I use CFE-223 powder ....its a harsher snappy type signature
Than compared to W-748 with is smooth and milder
---------------------------------------------------------------
Yet both in the same velocity range

 

[dellet]

Thats a very good point regarding 2 different powders
I know when I use CFE-223 powder ....its a harsher snappy type signature
Than compared to W-748 with is smooth and milder
---------------------------------------------------------------
Yet both in the same velocity range

What seems to be a good rule of thumb, the faster will be quieter. More powder burned, less muzzle pressure. It would likely show up in low light as less muzzle flash.

 

[DLT]

Interesting. I figured a few factors were at play just didn’t want to act like I knew what they were and sound like an idiot. I do have an adjustable gas block and a heavier buffer on my Grendel so maybe I could play with it. Or just get a longer barrel as I’m not happy with a Grendel anyways. Thanks guys

 

[HandgunHTR]

The others have covered barrel lengths and bolt vs AR, so I will chime in on another thing: Tone

Tone is something that each of us interpret differently. While the sound amplitude and frequency is constant, how each individuals ears hear it and their brains interpret it is not. For example, I have lost a lot of my high-frequency hearing in my left ear due to various things (not the least of which is gunshots) so suppressors that emit a higher frequency tone actually sound deader to me than they do someone with perfect hearing. This is why I lean more towards Ti suppressors.
Tone plays a big role in how suppressors sound to individuals. The dB rating only focuses on amplitude. That is why two suppressors with the same (or extremely similar) dB ratings will sound different to people.

 

[Coyotefurharvester]

Internal volume/componets and mechanics also are part of performance. That's why there are specifications/limitations on use for suppressors. Factors such barrel length, cartridge pressure, rate of fire and of course caliber. I have 2 18" AR 223 one is rifle length, on mid length gas. I have 2 very different suppressors I run on them, they sound different with each combination. One setup I only hear the bolt/buffer movement and others nearby say it sounds like a Ruger 10/22. When I have kids/new shooters I setup with that combo, minimal noise and recoil plus just foam ear plugs and eye protection. Makes communication easier. My full auto rated suppressor also produces the dirtiest fired brass, could probably reduce that by changing to a superlative gas block.

 

[Old Navy]

Interesting. I figured a few factors were at play just didn’t want to act like I knew what they were and sound like an idiot. I do have an adjustable gas block and a heavier buffer on my Grendel so maybe I could play with it. Or just get a longer barrel as I’m not happy with a Grendel anyways. Thanks guys

Are you wearing hearing protection?

 

[DLT]

Are you wearing hearing protection?

While out coyote hunting I do not, but it’s maybe 1 or 2 shots a week at most with my suppressor on

 

[Evlshnngns]

Ar's are just xxxx loud out of the ejection port, always.

Would a KAK down gas BCG be worth it for noise reduction?

 

[gunsandgunsmithing]

All else equal, bbl length is a huge factor just by getting the release point even an inch or so further from your ears. Yes, it makes a BIG difference, all by itself. Sound travel through air and dissipates rapidly with distance. Never thought about calculating it but probably a square root function but maybe even more than that.

 

[DLT]

All else equal, bbl length is a huge factor just by getting the release point even an inch or so further from your ears. Yes, it makes a BIG difference, all by itself. Sound travel through air and dissipates rapidly with distance. Never thought about calculating it but probably a square root function but maybe even more than that.

I would say it’s the main factor

 

[C.E.Smith043]

Probably an easy question for many on here but I have not owned a suppressor long at all and have only shot mine on a 16” 6.5 grendel a.r. platform. It’s a huge noise reduction don’t get me wrong but it still catches me off guard with how loud it actually is. Today I shot it on my 26” 6xc bolt gun and it feels like it’s half as loud even though it’s going 500fps faster than the Grendel, it’s absolutely a pleasure to shoot even with out ear protection. My cousin has a “supposedly” better suppressor he shoots on his 22” .243 and it’s loud as crap to me too. Is it the extra barrel length why it seems so much more quieter than my grendel and his .243 ? A 6xc and .243 win is very close in speed and powder cap.

The extra barrel length and the fact it's a bolt gun makes the difference

 

[dellet]

All else equal, bbl length is a huge factor just by getting the release point even an inch or so further from your ears. Yes, it makes a BIG difference, all by itself. Sound travel through air and dissipates rapidly with distance. Never thought about calculating it but probably a square root function but maybe even more than that.

I would say it’s the main factor

It depends on where you are in relation to both the muzzle, and in case of a semi auto, the ejection port. There are very specific microphone placement measurements for decibel testing for a reason.

To the shooter, a 26” bolt action will be quieter than a 26” AR. But a14” bolt action will also have less noise to the shooters ear than the AR, but more than the 26” bolt action. With that said, those results could be manipulated with powder choice. To a certain extent you can load for accuracy, velocity or noise level. Generally needing to compromise one to maximize the other two.

First thing to do comparing the two cartridges and two suppressors would be to be able to shoot both rifles/cartridges through both suppressors. Then use both powders in both cartridges. Then you might have some data to work with.

To go from acceptable without ear protection to loud as crap with the same bore size, it’s not the 4” of barrel on a bolt action that’s the problem

 

[1shot]

What seems to be a good rule of thumb, the faster will be quieter. More powder burned, less muzzle pressure. It would likely show up in low light as less muzzle flash.

^^^^^^^^^^^^^^^ THIS!!
i have found this to be true not only in rifle calibers, but PCC with straight blow back actions. All of my PCC have between a 5"-8" barrel, so you really can tell the difference, as opposed to longer rifle barrels.

Lloyd