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Supressor and Baffles Question

Ebenv

Plastic
Joined
Jun 23, 2010
Location
New Zealand
Hi There,

Before I start. In New Zealand, where I live, Supressors are legal so I am not trying to make something that could land me in trouble here.... LoL

I bought a suppressor for my .22 not too long ago. It is not working bad but thought I could build a larger one that might work better by allowing for more space in the chambers and more chambers.

OK, Ill try to describe what I did here:

All the chambers are 22mm in diameter. 1x40mm long, 1x30mm, 1x20mm, 1x10mm, 4x5mm. Each baffle only has the hole that the bullet travels through a 7mm hole as was measured on the other supressor. measuring the .22 bullet it measures 5.6mm which gives me about 0.7mm gap between the bullet and the wall of the baffles...

I finished the suppressor last night and tested it today but must say I am a bit dissapointed. The little one only has two chambers about 15mm in diameter and about 60mm long and it is still a lot quieter than the bigger one I built... I am not sure why this would be... One thought is that I might have to drill small little holes in the baffles to allow the gasses to expand to the other chambers too, but this should be possible through the hole the bullet travels so I am not sure.. I tried to attach the plans of what I built to give you an idea of what I have done but that did not work, so if you want more detail and thing you might be able to help me them please let me know if I need to send you the plans, they are in PDF format...

If someone can give me advice on what I can do to make the suppressor I built to do its job better it would be much appreciated.
 
Although I'm far from expert on the matter, it sounds like you've built a can with a stack of flat baffles, which basically give you multiple expansion chambers but little turbulence, which is really what causes the noise reduction.

Most .22 suppressors use K baffles. You can learn much more by registering at http://[URL="http://[Uhttp://www.silencertalk.com and looking in their 'smithing forum.
 
I'm no expert either, but from building internal combustion mufflers of that ilk, I would say that the smallest chamber should be the first one that the blast encounters. you may have it this way, but from the description it sounds (NPI) the other way around.


Herb Kephart
 
This may be helpful. This is how I make my K baffles.
KBaffle.jpg


Group1-9_150_.jpg




Group10-19_150_.jpg


Some more information; http://bbs.homeshopmachinist.net/showthread.php?t=35021
 
One thing Hiram Maxim discovered when he was designing suppressors is that there needs to be an expansion chamber at the inlet end of. For his Model 1922 22 rimfire suppressor the baffles didn't start until about 2" down the tube. Then the remaining 4 or so inches was baffled with stacked, stamped sheet metal baffles that looked like distorted miniature bottle caps. The tube dia was 1" or maybe a little less. It's been awhile since I have seen the internals, so my dimensions may be a bit off. They are close. Anyway the suppressor worked very well, I thought. With subsonic ammo in a rifle out in the open, the firing pin click was nearly as loud as the muzzle blast.

RWO
 
One thing Hiram Maxim discovered when he was designing suppressors is that there needs to be an expansion chamber at the inlet end of. For his Model 1922 22 rimfire suppressor the baffles didn't start until about 2" down the tube. Then the remaining 4 or so inches was baffled with stacked, stamped sheet metal baffles that looked like distorted miniature bottle caps. The tube dia was 1" or maybe a little less. It's been awhile since I have seen the internals, so my dimensions may be a bit off. They are close. Anyway the suppressor worked very well, I thought. With subsonic ammo in a rifle out in the open, the firing pin click was nearly as loud as the muzzle blast.

RWO
There have been a lot of innovations since Maxim designed his suppressors. Those style baffles are considered crude by today’s standards.

I have/own a suppressor with stamped steel cone baffles similar to Maxim. The upgrade to modern K baffles is quite significant in sound suppression. This is an integral 10/22 made by John's Guns many years ago. The baffles have been upgraded. His silencers now use K baffles.

802Integral35_.jpg

Most suppressors suffer from what is referred to as First Round Pop, where the silencer is very loud on the first shot, and quiets down after that. This is due to a large amount of oxygen in the tube, and during the first shot all the oxygen is used up. The follow up shots are much quieter than the first one. A properly designed silencer with a smaller expansion chamber usually minimizes the FRP.

Most 22lr silencers nowdays have a much smaller expansion chamber in the ½ to 1 inch range. (Centerfire suppressors need a much larger expansion chamber.)
 
I have a question is this k cone also usable on a larger cal such as the 30 cal or the 338.federal? Im thinking on he 338 . on a styker with a 14 inch tube or maybe a 16 i think this would be a intresting build
 
I have a question is this k cone also usable on a larger cal such as the 30 cal or the 338.federal? Im thinking on he 338 . on a styker with a 14 inch tube or maybe a 16 i think this would be a intresting build
Many of the centerfire suppressors use a cone baffle with a spacer. K baffles are usually used with rimfire (but not always). Different manufacturers use different styles. They want the most suppression in the smallest and lightest package.
aaccyc1.jpg
 
Thank you very much for all the replies...

First of all. Yes the baffles in the one I made are flat. I suspected from the start that this might be the reason why it is not working very good but what confused me was that the much smaller silencer I made only had one flat baffle in the middle of it held in place by two compression springs on either side of it...

My brother suggested that it might be because of the compressio nsprings that it might be working better... His argument is that while the gasses expand into the first chamber it forces the baffle to move forward slightly and then as the bullet goes through to the second chamber along with some of the gasses the baffle comes back... But I am not too sure if this will have much of an effect if it is the shape of the baffle that needs to cause turbulence in the moving gasses that will cause the silencing effect...

I have one end of my silencer threaded so I can allways do away with the flat baffles and make up some K-baffles. I did notice however that there ares lightly different ways of creating the mouse hole in the K-baffle. Is there any reason for one method to the other or will it work as long as the gasses has some place to escape into the rest of the chamber?
 
Suppression works by slowing and controlling the expanding gases and to a lesser effect, absorbing heat (i.e. energy). The mouse holes create a “cross jet” of turbulence that disrupts those expanding gases. The mouse holes are 180º from the bottom to the top.

The bottom of the K baffle collects the pressure, and the mouse hole directs the jet of gas across to the top mouse hole creating the cross jet effect, thereby delaying the gas out the front, and absorbing energy. Also used in centerfire suppressors.

In a previous post there is a photo of a John’s Guns integral. Note the copper wool wrapped around the barrel. That copper wool was wrapped around the ports to absorb the heat (energy). This increased the effectiveness of the poor designed baffle system. These heat sinks, are not used for muzzle cans, and have mostly been phased out of modern integrals.
 
Cone shaped baffles are the best in my opinion. I have used K shaped and 60 degree cones, but will try step cones next. Any baffle that makes the gas flow reverse onto itself is going to do a much better job than a flat baffle.

I would make the baffle bore at least 1 millimeter larger than bullet diameter to prevent baffle strikes that ruin accuracy. If the silencer does not align perfectly with the bore, make the bore larger as they get farther from the muzzle.

I think smaller expansion chambers are better. Use a tough metal like stainless steel for the blast baffle to resist erosion. The more back pressure and turbulance you create, the better the suprpession.

I use spacers and end cap compression to keep the baffles in place. Springs just add too much weight.

Ranb
 
Ebenv,

Your sprung moderator sounds like the "Manders" .22 moderator that came from Kiwi-land in the 1980s. I tried one (once!), but found that the front end baffle never returned to the same place and both noise and accuracy were poor, so it got relegated to use as a thread protector, and the Parker Hale went back onto the gun again

Have you seen the Frankford arsenal report on silencers?

Although they were testing old designs, frequently with rubber "wipes" (wear out fast and destroy accuracy - until they wear out), they did a pretty good job of using an oscilloscope to identify where the different sound peaks were coming from.

Interestingly, a Maxim moderator was one of the most effective ones they tested.
 
Many people will poke fun at the old Maxim suppressors as being old and out of date. But look at the results of testing. Many of Maxims test very well compared to modern ones and they are very simple.

Remember Maxim was making things in a different time, cheap and in bulk was the important thing, remember it was an unrestricted product for the general shooting public. Getting the firearm reduced to an acceptable level of noise was what was important.

People will debate about who is making the quietest design, but the difference is often so subtle that only a meter can distinguish and often the firearm and ammo will have a large effect on which is going to work the best.

Long story, short. Look at the old Maxim designs, they were very simple and worked well. There were a lot of marginal designs that were made by fancy engineers in during the Vietnam era that were worse then what Maxim had made a long time before.
 
I finished my AR-15 step cone silencer and shot it against the K baffle silencer I made last year. The step cone can was shot on a 16" carbine and the K baffle can was mounted on a 20" Hbar. The shooters said the step cone can was a bit louder and higher in pitch, probably due to the shorter barrel.

YouTube - ar-15's with homemade silencers The order of the shooting is unsuppressed, K baffle then step cone.

Ranb
 
Being generally accepted that the "k" baffle is the preferred style baffle, the next question is where do you get or how do u make. I have a viable alternative. It is certainly less expensive and time consuming. I have found the results of negligible difference. The following link provides an inexpensive $2.55 baffle for a 22 cal. There are many other options available on the site. http://www.kaidomain.com/p/S021805.24_9mm-D-x-19mm-H-OP-Reflector-1-piece
 
In the airgun world some cans (they call them LDC for lead dust catcher ;-) ) are made with the original expansion chamber containing what looks like a engine valve, bored, and with the stem pointed towards the muzzle.
This allows the bullet to "plug" the bore, and the gasses are sent towards what would be the valve base. After that the baffle designs vary somewhat, but my experimentation shows that this original chamber accounts for the majority of attenuation, and reduces the required total volume required.

Even easier to make the same design, with additional first expansion chamber extending rearward over the portion of barrel you've inserted into the can.

FOR CLARITY
what I mean is essentially a elongated first cone, with a narrow bore and long neck, so that most of the gasses bypass the actual exit bore, make the rest of the baffles how you will.

I have not tried this on a firearm, as they are still (whatever you'd like to call it) stateside.

You could google "Benjamin Marauder baffles", though I'm not saying THOSE ONES would hold up in a powder burner, they are cheap!

EDIT
Thanks to Ron for the pictures! Very brave of you! ;-)
 
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What a great thing to be able to experiment without the threat of a ten year prison sentence hanging over your head! I designed one many years ago but am unwilling to jump through the meaningless irritating hoops and give more money to the government for what they should have no involvement in to actually build one.
 
We used to make silencers with a larger diameter tube, and fill it with washers the had an elongated hole the bullet diameter and elongated out to the very edge..even going full to the Id of the larger bore..then we would stack them in all going different ways..Yes with a threaded end to close all in the tube...Good to start with watching the fire flair out..because often a silencer had to be about that long..
 
It is interesting to google "22rf silencers" and click on "images" to see the wide variety of designs out there. My impression is the monocore designs are slowly becoming the dominant commercial design in 22 rf.

RWO
 








 
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