Pistol vs Rifle

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Pistol vs Rifle

Post by mcrump » Tue Feb 09, 2016 8:06 pm

I have a 8 K-baffle can that when I screw it onto my Walther P22 it's as quiet as a church mouse, but when I screw it onto my Ruger 10/22 rifle it seems a heck of a lot louder. I'm using the same Winchester subsonic ammo. Is this par for the course? Do pistol and rifle can internals differ in some aspect even when it's the same caliber? Thanks for any enlightenment.
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Re: Pistol vs Rifle

Post by CMV » Tue Feb 09, 2016 8:53 pm

My very first project was like this. Good on a 22/45, marginal on a 10/22.

Post pics of your internals. There is work needed on your K's to make them perform better or design better for your next project.

Also - 10/22 has pretty loud action noise.
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Re: Pistol vs Rifle

Post by mcrump » Tue Feb 09, 2016 9:16 pm

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Re: Pistol vs Rifle

Post by mcrump » Tue Feb 09, 2016 9:58 pm

On my pistol, all I hear is the action. On the rifle, there is definitely muzzle noise.
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Re: Pistol vs Rifle

Post by T-Rex » Tue Feb 09, 2016 10:12 pm

FYI
Winchester 22lr Super-X Subsonic muzzle velocity is posted as 1065.
I know this is under 1125, by a bit, but other factors remain.
If I took this ammo out of my warm basement, put it inside my warm jacket, went outside (where it is currently 26F) and fired it down a warm barrel, there is a good chance it will go supersonic.
Im not saying all this happened, I just wanted to state another possibility past what was already offered.

And no, 10/22 actions are not known for being uber quiet.
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Re: Pistol vs Rifle

Post by Capt. Link. » Wed Feb 10, 2016 3:57 pm

The baffles are being worked harder with the higher velocity gases of the pistol.You can tune the porting for the pressures involved.
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Re: Pistol vs Rifle

Post by mcrump » Thu Feb 11, 2016 8:59 pm

It sounds like you are saying that the higher velocity gasses of the pistol make it quieter? That seems backwards to me, or am I missing something. I would love to understand about tuning the porting. Can you elaborate?
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Re: Pistol vs Rifle

Post by jlwilliams » Fri Feb 12, 2016 8:25 am

There are a couple factors at play. One is that the longer barrel may be letting the rounds go super sonic. Another is that when you fire the rifle, the bullet pushes the barrel full of air into the silencer really fast, filling the volume with that before the cartridge gas goes in. There is a name for that effect that I don't remember and it may or may not be BS that I heard somewhere so take it with a grain of salt. I read it online so maybe it's true. There are more variables, but what you need is a solution.

Whatever the actual, scientific cause is, the fix revolves around the fact that there are three legs to the stool. The gun, the can and the ammo. It takes a balance between these three variables to get good suppressed performance. In this case, you have one can that remains constant and you are trying to use one ammo but when you use one can and one ammo with two guns you get different results. It seems likely that what you need is different ammo in the different guns. I'd try that before messing with the hardware.

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Re: Pistol vs Rifle

Post by T-Rex » Fri Feb 12, 2016 8:38 am

mcrump wrote:It sounds like you are saying that the higher velocity gasses of the pistol make it quieter? That seems backwards to me, or am I missing something. I would love to understand about tuning the porting. Can you elaborate?
I believe the good Capt is trying to show how modern baffle designs thrive on pressure, to disrupt and distort the gas flow. The pressure would be higher in a pistol vs rifle and would therefore provide an optimal environment for the baffles design.

Forgive me if I'm misinterpreting.
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Re: Pistol vs Rifle

Post by Historian » Fri Feb 12, 2016 10:48 am

jlwilliams wrote:There are a couple factors at play. One is that the longer barrel may be letting the rounds go super sonic. Another is that when you fire the rifle, the bullet pushes the barrel full of air into the silencer really fast, filling the volume with that before the cartridge gas goes in. There is a name for that effect that I don't remember and it may or may not be BS that I heard somewhere so take it with a grain of salt. I read it online so maybe it's true. There are more variables, but what you need is a solution.

Whatever the actual, scientific cause is, the fix revolves around the fact that there are three legs to the stool. The gun, the can and the ammo. It takes a balance between these three variables to get good suppressed performance. In this case, you have one can that remains constant and you are trying to use one ammo but when you use one can and one ammo with two guns you get different results. It seems likely that what you need is different ammo in the different guns. I'd try that before messing with the hardware.

+1

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Re: Pistol vs Rifle

Post by Fulmen » Fri Feb 12, 2016 12:12 pm

I've yet so try a can that was louder on a rifle than on a pistol. The can might be more effective on a short barrel, but it's so much louder to begin with you will never get less sound. I can think of two reasonable explanations for OP's experience:
1. The round is super (or trans)sonic out of the rifle. This can happen even with subsonic ammo, even though it's rare.
2. Bullet contacting the can. I've had this on occasions, and they've often caused the round to be louder.

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Re: Pistol vs Rifle

Post by 0101silent » Fri Feb 12, 2016 1:48 pm

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Re: Pistol vs Rifle

Post by Capt. Link. » Fri Feb 12, 2016 3:45 pm

T-Rex wrote:
mcrump wrote:It sounds like you are saying that the higher velocity gasses of the pistol make it quieter? That seems backwards to me, or am I missing something. I would love to understand about tuning the porting. Can you elaborate?
I believe the good Capt is trying to show how modern baffle designs thrive on pressure, to disrupt and distort the gas flow. The pressure would be higher in a pistol vs rifle and would therefore provide an optimal environment for the baffles design.

Forgive me if I'm misinterpreting.

Higher velocity gases work baffles harder and exhibit higher SPL loses then lower velocity ones.You can see this with a meter and hear it when changing pressure and velocity of the gases.

Every suppressor has a sweet spot for velocity & pressure of the gases because of baffle design and porting details.I have one suppressor that is fantastic on a rifle but marginal on a pistol w/ identical ammo.I believe the AAC Element suppressor was specifically tuned for the high pressure gas of .22 pistols as a example.

I do not disagree with Mr jlwilliams in that a super sonic round will sound disproportionately louder than a subsonic projectile in rifle and pistol.Most people can hear the difference without the need for a chronograph.I am not talking about or referring to a transonic bullet or its speed only the differences in gas velocity and pressure when switching barrel length.

Bullets that are subsonic in a 24.00" barrel will be slower in a 4.00" pistol length one.The only difference between the two is the velocity & pressure of the gases.You can hear the difference that many suppressors exhibit when changing from rifle to pistol length barrels without any bullets going supersonic.I have heard this many times as have others.

If you can't detect any change your baffles porting is effective or ineffective over a wider range of pressures congrats.
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Re: Pistol vs Rifle

Post by ranb » Fri Feb 12, 2016 6:52 pm

mcrump wrote:I have a 8 K-baffle can that when I screw it onto my Walther P22 it's as quiet as a church mouse, but when I screw it onto my Ruger 10/22 rifle it seems a heck of a lot louder. I'm using the same Winchester subsonic ammo. Is this par for the course? Do pistol and rifle can internals differ in some aspect even when it's the same caliber? Thanks for any enlightenment.
Did you measure the ammo velocity to ensure it stays subsonic in the rifle? My suppressed P22 is much louder than any suppressed 22lr rifle.

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Re: Pistol vs Rifle

Post by whiterussian1974 » Sun Feb 14, 2016 4:59 pm

jlwilliams wrote:Another is that when you fire the rifle, the bullet pushes the barrel full of air into the silencer really fast, filling the volume with that before the cartridge gas goes in. There is a name for that effect that I don't remember and it may or may not be BS that I heard somewhere so take it with a grain of salt. I read it online so maybe it's true. There are more variables, but what you need is a solution.
https://en.wikipedia.org/wiki/Precursor_(physics)

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But in this case, it happens to be true.)

And there are multiple sound sources involved. They are broken into 4 main parts. But even the Blast component can be parsed into many threads.

Muzzleblast wouldn't matter much if fired in a 12kpsi atmosphere, or a 0psi (vacuum) transition medium. Each for a seperate reason. The first wouldn't generate a concussive blast differential, the second wouldn't transmit the vibration.
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Re: Pistol vs Rifle

Post by mcrump » Mon Feb 15, 2016 7:58 pm

CMV wrote:My very first project was like this. Good on a 22/45, marginal on a 10/22.

Post pics of your internals. There is work needed on your K's to make them perform better or design better for your next project.

Also - 10/22 has pretty loud action noise.
OK, if you have seen my k-baffles, what suggestions do you have. I have installed a rubber bumper where the bolt meets the receiver which has helped with action noise but I swear it's the "pop" that I am hearing. Do you think a blast chamber would help? I could remove the first baffle and replace it with an appropriate spacer. I also read that sometimes drilling a hole in the face opposite the scoop of the first baffle helps, although I don't recall the name of that technique.
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Re: Pistol vs Rifle

Post by whiterussian1974 » Tue Feb 16, 2016 2:17 am

mcrump wrote:I also read that sometimes drilling a hole in the face opposite the scoop of the first baffle helps, although I don't recall the name of that technique.
Don 't remove the 1st baffle. It would only add 1st rd pop.

The term for the hole is Dater Hole after Philip Dater, PhD. It needn't be opposite the scoop, but many designs place it there.

You are probably getting rds in the Transsonic range. The only way to test would be to cool them in your freezer over night and see if there is any change b/f firing a room temp rd. But even then the cold temp might not slow the burn enough to drop 85-100fps.

Try another brand of subsonic ammo and see if the rifle is still louder. Then we'll have more data points to eval.
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Re: Pistol vs Rifle

Post by CMV » Thu Feb 18, 2016 6:26 pm

mcrump wrote:
CMV wrote:My very first project was like this. Good on a 22/45, marginal on a 10/22.

Post pics of your internals. There is work needed on your K's to make them perform better or design better for your next project.

Also - 10/22 has pretty loud action noise.
OK, if you have seen my k-baffles, what suggestions do you have. I have installed a rubber bumper where the bolt meets the receiver which has helped with action noise but I swear it's the "pop" that I am hearing. Do you think a blast chamber would help? I could remove the first baffle and replace it with an appropriate spacer. I also read that sometimes drilling a hole in the face opposite the scoop of the first baffle helps, although I don't recall the name of that technique.
As others have suggested it could be the velocity. Use a chrony & rule that out. CCI standard velocity is a good choice. All my rimfires eat it up & it stays subsonic even out of rifle-length barrels.

I haven't seen your baffles. Or the remainder of your build. Post real pictures. I deal with parts that don't look like the drawings all day long :) I don't use a blast chamber with rimfire K's. Maybe others do, but I like the face of that first K right up there at the muzzle almost. Enough space if your endcap is threaded without an internal shoulder that you won't have interference if you happen to get something with long threads, but otherwise pretty close to the muzzle. I don't think removing the first one will help you any.

If you made those baffles to the drawing & are using a .250 bore that could be the problem too. That's really tight & not a lot of margin for error. Run some jacketed (plated as the case my be) ammo and look for evidence of copper bits in the internals. Sometimes it's hard to see if a LRN is rubbing passing through a baffle but if it's shaving a little copper you'll see that easier. What's the accuracy like? I've had that happen too - a little contact on the way out. It was hard to diagnose & find the problem but the symptom showed up as rounds all over the place. That may or may not make a lot of noise when it happens. In my case the rifle was Hollywood so it didn't sound like anything was wrong. A baffle strike doesn't necessarily mean a catastrophic failure and the can grenades.
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Re: Pistol vs Rifle

Post by mcrump » Fri Feb 19, 2016 2:09 pm

http://s43.photobucket.com/user/mcrump2 ... 8.jpg.html

I have a hellova time getting photos to show.
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Re: Pistol vs Rifle

Post by doubloon » Fri Feb 19, 2016 2:40 pm

mcrump wrote:http://s43.photobucket.com/user/mcrump2 ... 8.jpg.html

I have a hellova time getting photos to show.
you have to copy the "DIRECT" link from photcrappit and then put it in IMG tags in your post like this

Code: Select all

[img]http://i43.photobucket.com/albums/e356/mcrump29732/IMG_0158.jpg[/img]
Image

Image
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Re: Pistol vs Rifle

Post by CMV » Fri Feb 19, 2016 6:14 pm

Those look pretty good. The port opposite the scoop looks small compared to mine but I've been told I make mine too big. But they work well.

What about clearance between the tube & the baffles? I'm at a loss. 9 of those K's should be working well. All I can suggest is what I wrote above - check the velocity on a chrony &then check for any evidence of the bullet rubbing somewhere on it's way thru. Get the baffles sparkly clean & fire a few rounds then inspect. It should show up.
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Re: Pistol vs Rifle

Post by T-Rex » Fri Feb 19, 2016 6:37 pm

Yeah, those Ks look gtg and 9 should be hush.

If you don't have access to a chrono, just buy some lower velocity ammo. But, remember, just because it says"standard" doesn't mean its subsonic.

Have you tried holding the bolt closed on the rifle?
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Re: Pistol vs Rifle

Post by mcrump » Sat Feb 20, 2016 12:44 pm

I think I had about .003 clearance between the front of the baffle and the tube wall and about .050 between the skirt and the tube wall. These dimensions were from generalized info on the forum.
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