Lose of noise reduction with oversize suppressor hole

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RondoChuck
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Lose of noise reduction with oversize suppressor hole

Post by RondoChuck »

There is a lot of discussion of drilling the suppressor clearance holes above or more than the nominal clearance with the cartridge by .04 to .060. What happens to the sound attenuation if you use a suppressor for a 9mm on a 22LR gun? Does the sound attenuation get reduced by some percentage? If I use a suppressor drilled for a 45 cartridge on a 9 mm pistol, what would the sound increase or change be from using a suppressor for a 9mm gun on a 9mm gun?
a_canadian
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Re: Lose of noise reduction with oversize suppressor hole

Post by a_canadian »

Funny you should ask. Just the other day I screwed a 1.5" x 10" suppressor with an 11.5mm bore, made for a 9mm carbine barrel, onto a break-action .22lr rifle with a 10" barrel and test fired it with CCI SV. The thing metered EXACTLY the same as the dedicated 1"x7" K baffle can I built for the .22lr rifle. Exactly the same impression to my ears as well. May as well have been using the same suppressor for both tests. The large one works great on an 18.6" carbine barrel shooting 9mm subs but was frankly unimpressive for its size on the .22lr. I'm not interested in making the effort of building such a huge, heavy can for the .22lr just to test whether it's slightly better, as the added weight would be silly on that little rifle. I don't doubt that it would be quieter with the correct bore size but that's not the question here. I suspect from this experiment that a smaller 9mm-specific suppressor mounted on a .22lr barrel would yield worse results owing to reduced air volume.
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whiterussian1974
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Re: Lose of noise reduction with oversize suppressor hole

Post by whiterussian1974 »

Overbore causes minimal increase in sound. A 9mm through the .45 might not even be noticeable to some ears. But there is a "slight" increase. Maybe 1 dB? If you use a 9mm endcap, it will reduce the difference even further. As long as the baffles generate significant turbulence, the added bore size will be largely mitigated.

For a .22 lr through 9mm: again, minimal.

The main difference will be the baffle types and what they are designed for. As a_canadian said, a purpose-built .22 can is every bit as effective as the larger can built for a carbine. The issue is all of the wasted volume that simply isn't utilized.

In summation: I typically use a "multi-cal" approach to limit the number of cans that I must buy stamps for.
1 - .375 magnum rifle
1 - rimfire
1 - centerfire pistol
Maybe 1 day 1 for a 10ga as well.
And if I ever buy a .50 BMG, I'll have a can on it for its 1st shot.
The Darkest Corners of Hell are reserved for those who remain Neutral!-Dante
The Death of One is a Tragedy, a million only a statistic.-Stalin
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