300 aac blackout subsonic. How loud is it with no supressor?

[rbstern]

Wilk sound like a 357 mag out of a carbine if no silencer. Might as well use supers if hunting with no can. Use ear plugs either way.

357 out of a carbine will almost always give a sonic crack, which is pretty loud, on top of the gases. That noise is absent with subsonic rounds.

 

[GAgunLAWbooklet]

Thanks buddy. Do you know how much barrel length matters. I read that all the powder is burned in just under 8 inches...

Barrel length has a different effect on velocity as it does on sound / noise.

The point at which you get very little additional velocity may be fairly short -- 8" or 12 inches with subsonic loads.

But you still get the benefit of reduced noise way out to a full length barrel. Sixteen, 18.5" even 22" inches. The longer the barrel, the quieter the bullet is when it exits.

That's because as long as the bullet is trapped in the barrel and has not exited the muzzle yet, the bore of the gun's barrel is like a pressure vessel --a cylinder shaped container that holds in compressed and heated gases. As the bullet moves from the chamber end of the barrel towards the muzzle end, it increases the volume of that sealed container, which reduces heat and reduces pressure. This is called Boyles Law, a well-known principle of physics.


Two years ago I gave a lecture about silencers and short-barreled weapons and NFA laws on them.
My presentation was followed by a silencer demonstration at the range out back.
I shot my .22 silencer, and somebody else (I believe a member of ODT) shot his 300 Blackout carbine (orvwas it an SBR?) both suppressed and unsuppressed using subsonic ammo.

The sub ammo was pretty loud, for us without hearing protection.
I'd say it sounded like a .410 or 20 gauge shotgun. or maybe you could say it was as loud as a 45 pistol but I don't think it was quite that loud --maybe if a .45 round were fired through a rifle-length barrel that would be more like it.

With the suppressor on, it sounded like a CO2 powered pellet gun.
Maybe on par with popping a brown paper bag, a lunch sack, by filling it with air and slapping it with your hand.

 

[NWSharpshooter]

Lots of bad information in here.

300 BLK subsonic is very quite because all the gasses have burned before the bullet exits the muzzle.

I was demoing a can on subsonic 300 BLK and took the can off to show how much louder it was and to show how effective the can was. I was slightly embarrassed when unsuppressed it wasn't a whole lot louder than suppressed.

I would compare it to 22 LR out of a 16" barrel.


MUCH quieter than any handgun!

 

[GAgunLAWbooklet]

Nw Sharpshooter, The laws of physics say otherwise. I think your perception was off.
Longer barrels = quieter report, even with subsonics, even with about the same % of gunpowder being burned in-bore.

 

[Plinker66]

Putting one of these on really helps throw the blast away, imo.

 

[NWSharpshooter]

Nw Sharpshooter, The laws of physics say otherwise. I think your perception was off.
Longer barrels = quieter report, even with subsonics, even with about the same % of gunpowder being burned in-bore.

I never said anything about barrel length but that doesn't matter. Longer barrels equals quieter report because more powder is burned before the bullet exits the barrel. Longer barrels also make the percieved sound quieter because it is further from your ear
..but not by much.


I'm not going off something I have read on the internet. I'm going off real world experience. 300 BLK subsonic is the quietest round I have ever fired unsupressed.

 

[NWSharpshooter]

Back to the OP though, plugs provide better hearing protection than muffs any so why you be worried?

 

[shootin4fun]

I dont think I've ever seen a blk without a can. Sorry man. Is this out of a bolt or gas gun? Gassers will always be louder because of port pop or piston pop. I would run a bolt gun if at all possible

I have an 8.5” BO with a Flaming pig. It does fine. Haven’t talked myself into any stamps for it.

 

[Plinker66]

I reckon Longer barrels are also quieter because they put more distance between the muzzle and the ear, which greatly increases the pressure dispersion.

Allowing 10” for ear to back of AR barrel, and assuming equal dispersion in all directions, the difference between an 8” and 16” AR barrel is significant...

18” x 18” x 18” = 5,832

26” x 26” x 26” = 17,576

 

[Fatal_Bert]

Back to the OP though, plugs provide better hearing protection than muffs any so why you be worried?

That's what I was thinking.