barrel length vs. sound db when suppressed (9mm)

[King]

I've been looking for info on the correlation between barrel length and sound db levels in 9mm suppressed but not having much luck.

Host gun will be a Sig MPX with an Octane 45HD running subs, mostly 147's. It has an 8" barrel but looking to chop and re-thread. Ideally, I'd like a length around 4.5", but would go longer if there will be a noticeable sound reduction on say a 6.5" barrel. So the question is what length to go with.


Traditionally the shorter the barrel, the more pressure and louder the shot. However, FPS will increase with barrel length and possibly increase flight noise. I don't imagine I would be pushing super sonic with 147's anyway. Is there a sweet spot or will I even hear much of a difference between a 4.5" and 8" barrel?

[sako55]

When I was researching my AR 9 build, it seemed that the 5.5 inch barrels was the sweet spot. This is about the length of the barrel on a full size handgun.

[MarkCO]

The sweet spot is in the 8 to 9 inch range. Shorter than that is louder, longer and you end up potentially losing some shootability and maybe even accuracy. Specific bullet and powder does matter.

[ThunderSquirrel]

My setup is 5.5" with a TiRant9. Super quiet with 147s.

[Rooskibar03]

I recently cut my MPX down to 4.5 and it's just as quiet now as when I ran it full length. I was running an Osprey 9 when it was full length and now I've got an Omega 9K.

My favorite gun.

[King]

Awesome Rooskibar. Thanks for the video. Looks like I'll go 4.5

[mattiooo]

I recently cut my MPX down to 4.5 and it's just as quiet now as when I ran it full length. I was running an Osprey 9 when it was full length and now I've got an Omega 9K.

My favorite gun.

Nice run on those pins. I really love the look of that MPX.