The Hush Hole?

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quietoldfart
Senior Silent Operator
Posts: 104
Joined: Mon Jan 27, 2014 4:28 pm
Location: France

Re: The Hush Hole?

Post by quietoldfart » Thu Feb 05, 2015 6:05 am

Thank you very much for the response, that is helpful. It seems that from your experience with your very flexibly designed rimfire suppressor that while certainly an interesting phenomenon, the Hush hole in the middle of the baffle stack is not a definitive, or 'must have' solution. Even if it is being used with an ablative liquid, it sounds like your rather small micro suppressor out-performs that fairly substantially long .22" suppressor with the Hush hole, if I'm understanding you correctly. So parabolic baffles eh? I am not clear on the 'air wipe' reference at all, unless that refers to the lightness of the 1/32" materials thickness.

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LavaRed
Silent But Deadly
Posts: 1830
Joined: Sun Apr 05, 2009 8:11 pm
Location: CA

Re: The Hush Hole?

Post by LavaRed » Thu Feb 05, 2015 3:45 pm

quietoldfart wrote:Thank you very much for the response, that is helpful. It seems that from your experience with your very flexibly designed rimfire suppressor that while certainly an interesting phenomenon, the Hush hole in the middle of the baffle stack is not a definitive, or 'must have' solution. Even if it is being used with an ablative liquid, it sounds like your rather small micro suppressor out-performs that fairly substantially long .22" suppressor with the Hush hole, if I'm understanding you correctly. So parabolic baffles eh? I am not clear on the 'air wipe' reference at all, unless that refers to the lightness of the 1/32" materials thickness.
Yes, basically the Hush Hole does work, but there's stuff that can outperform it, and it only seems to work with .22LR. Also, it does tend to get clogged up, and making it too large reduces its effectiveness.

Yup, parabolic baffles have been a staple of my most silent designs. However, they have one grave flaw. They seem to consistently de-stabilize the bullet on the last baffle, eventually causing baffle strikes. We endlessly theorized about the causes on here, but nothing conclusive was ever reached, and eventually I settled for sacrificing a little suppression for more conventional designs like K's.

The Air Wipe principle works by channeling some gas flows to jet across the bore just as the bullet is passing, significantly disturbing the bore jet flow. It works better than expected, but requires quite a lot of timing to get right. This is a different suppressor, CF tube with a Titanium monocore. and standard 1" OD x 5.75" long. While not as quiet as the micro-can, it's quiet enough for indoor plinking and it's very durable. I've done heavy mag dumps with it (once shot through 50 rounds just mag after mag), just to test it, and it help. The CF didn't even fail when it was too hot to hold. Actually had to drop it in water that time.
"There are no stupid questions, only stupid people". -MAJ MALFUNCTION

quietoldfart
Senior Silent Operator
Posts: 104
Joined: Mon Jan 27, 2014 4:28 pm
Location: France

Re: The Hush Hole?

Post by quietoldfart » Thu Feb 05, 2015 7:58 pm

Hm. Some sort of acoustical destructive interference causing the bullet to vibrate perhaps? Shapes contribute in often startling ways to the behaviour of sound, and since you're saying a parabolic baffle behaves differently (better, from a suppressor builder's perspective) than other baffle shapes, it stands to reason that the negative aspects might also be different. Perhaps there's not only a law of diminishing returns with suppressor efficiency, but actually a law of reversing returns, where past a certain decibel reduction one risks interference patterns of various sorts depending on the geometry of the baffles.

CF getting hot scares me a little. Epoxy is the glue holding all that fibre together, and no epoxy I know of can be heated beyond about 450 degrees Fahrenheit without becoming soft and probably suffering permanent degradation. Perhaps your tube only got close to that limit? I'd not want to push magazine dumps through CF from anything bigger than .22"LR to be sure, what with various larger calibre suppressors glowing red in such use.

dark2023
Silent Operator
Posts: 65
Joined: Wed Aug 27, 2014 6:28 pm
Location: North Carolina

Re: The Hush Hole?

Post by dark2023 » Sun Feb 08, 2015 5:01 am

This "hush hole" idea is quite unique, I wonder if any of the larger suppressor companies have played with similar prototypes before.
A gun is meant to protect your life, not your wallet. Things can be replaced, people cant.

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