lets discuss various port noise levels of suppressed semi auto platforms

Gordon · Apr 22, 2022

I am interested in peoples experiences, perceived or measured from various semi auto platforms.
I'll go first: the S&W 422 with the longer 6" barrel and subsonic ammo is slightly quieter than the similar 6 7/8 barrel length Ruger Mark 1 with the same suppressor and ammo - Observed yesterday !

The Ruger 10-22 TD 16" barrel is slightly louder with same ammo and suppressor as the Colt /umerex(Walther) 16" barreled M4 Clone

The Beretta 92 S is quieter than the Sig 226 or Glock 19 with about same length barrel and suppressor and ammo

Thats it for me so far. Hearing about MachIVshooter post about the S&W Gen1,2- 3 guns being quiet.

The Glockodile · Apr 22, 2022

Gordon said:
The Beretta 92 S is quieter than the Sig 226 or Glock 19 with about same length barrel and suppressor and ammo

That's something like 5", 4.5", 4" there...

Gordon · Apr 22, 2022

The Glockodile said:
That's something like 5", 4.5", 4" there...

with threaded barrels I have only 1/2" apart pretty much , I don't think that matters we are talking obvious loud noises and seems like from the unlocking of port to me.

G19= 4.5" P226 = 4.9" 92= 5"

N555 · Apr 22, 2022

All standard weight and velocity 22lr loadings will be rendered subsonic in a 4.5 inch barrel.

Gordon · Apr 22, 2022

I know that, I am shooting advertised 1080 FPS from rifle velocity ammo in a 6" barrel and tey are just over a thousand FPS with 30 fps variation . They are indeed subsonic !
I long ago adjusted the main spring on the Walther "M4" Clone .22 to be reliable with that cheap CCI Standard Velocity stuff I bought when very cheap. It feeds great in all my guns , the real old stuff eats it up with no battering.

Zak Smith · Apr 26, 2022

It can also change depending on ammo. I've seen a HK USP be quieter than a Glock 17 with some ammo (which is ostensibly "expected"), but louder with other ammo.

Comparing mil-left to mil-right and the shooter's-ear number can also show when the MR number is dominated by port pop vs. actual muzzle report.

Zak Smith · Apr 26, 2022

Here's some data:

Please note the caveats/notes at the bottom of the screen shot.

These are peaks only, specifically the peak of whatever noise was loudest at that mic location (ML, MR, SE).

As you can see in the graph from Ray's post above, the port pop and/or action noise are shorter impulses compared to the overall gas venting from the front of the suppressor.

If you see a ML peak a lot louder than the same data in the 300 BK BOLT ACTION thread, it's because port noise dominates.

Gordon · Apr 28, 2022

Wow , very interesting Zak.

Gordon · May 2, 2022

After this weekend load development the ammo indeed is a large factor !
My son and I fooled with various 9 mm subsonic recipes on the Dillon and came up with 6.6 grains AA 7 powder under a 147 plated round nose which was just under 1000 fps in 6" Ruger charger down to 4" SIG 239 or Glock 19 at 950 fps. The Dillon is now set for that as we go 100 percent function and it's accurate to 50 yards .it is much quieter than factory 147 grain ammo we tried and heavier loads of AA7 and a couple other powders. We have 6 pounds of AA7 .
On Sunday we worked on .300 Blackout subs for our 8" pistol gassed pistols and a 16" switch barrel upper. With the Pistols we found imr 4227 we have been loading .45 Colt with to be excellent in .300 Black with my " seconds" sierra 220 grain hollow point s I bought a thousand of. These Sierras came with a canalure at the approximate correct height for .300 BO use. We backed off the charge Incremental until one of the uppers would notlick open and raised it .5 grains from that and those were 1010 fps from that upper and a little slower from the other at 990 fps and 1030 fps from the 16" barrel. Charge was 9.7 grains of imr4227 with a slightly opened ( uniformed) charge hole and old Remingy 6 1/2 primers I have a 1000 of from .22 hornet days. The Phoenix IV or Aquilae suppressors were extremely quiet on that load and printed around a inch or two at 50 yards with those 1 x optic pistol uppers.
So now We have two good subsonic loads . .

gotboostvr · May 2, 2022

Gordon said:
After this weekend load development the ammo indeed is a large factor !
My son and I fooled with various 9 mm subsonic recipes on the Dillon and came up with 6.6 grains AA 7 powder under a 147 plated round nose which was just under 1000 fps in 6" Ruger charger down to 4" SIG 239 or Glock 19 at 950 fps. The Dillon is now set for that as we go 100 percent function and it's accurate to 50 yards .it is much quieter than factory 147 grain ammo we tried and heavier loads of AA7 and a couple other powders. We have 6 pounds of AA7 .
On Sunday we worked on .300 Blackout subs for our 8" pistol gassed pistols and a 16" switch barrel upper. With the Pistols we found imr 4227 we have been loading .45 Colt with to be excellent in .300 Black with my " seconds" sierra 220 grain hollow point s I bought a thousand of. These Sierras came with a canalure at the approximate correct height for .300 BO use. We backed off the charge Incremental until one of the uppers would notlick open and raised it .5 grains from that and those were 1010 fps from that upper and a little slower from the other at 990 fps and 1030 fps from the 16" barrel. Charge was 11.6 grains of imr4227 with a slightly opened ( uniformed) charge hole and old Remingy 6 1/2 primers I have a 1000 of from .22 hornet days. The Phoenix IV or Aquilae suppressors were extremely quiet on that load and printed around a inch or two at 50 yards with those 1 x optic pistol uppers.
So now We have two good subsonic loads . .

I'd call that a success (and a good way to spend a weekend)!

lets discuss various port noise levels of suppressed semi auto platforms

Gordon

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The Glockodile

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Gordon

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N555

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Gordon

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Zak Smith

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Zak Smith

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Gordon

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gotboostvr

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