Suppressor baffle design - single assembly

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Fri Jan 28, 2011 5:33 pm

I'm thinking about building a suppressor with this kind of internals...

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Would this kind of design be suitable for a pneumatic? Its going to be for a 13mm ID barrel, approx muzzle velocity of 222m/s, shooting drag stabilized ammunition.
Also, how much clearance do I need between the projectile and baffle walls?
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linuxexorcist
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Fri Jan 28, 2011 9:55 pm

Some experimentation would have to be done to figure out clearance for the projectile, though i think ~10-15% of the diameter would be fine. It would also depend on the stability of the projectile.

I think you could make this with a drill press, epoxy and some patience, hold on, i'm gonna sketchup this

UPDATE

I'm back:
Image
You could probably do that, the hole down the middle would be a barrel piece, with epoxy cast around it, then some holes drilled, and the whole thing sleeved and sealed

I'm thinking that, while this design looks interesting, it's not worth the work compared to a regular-style suppressor
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Sat Jan 29, 2011 12:37 am

Ah, the making-propelling-gasses-think-"where-the-heck-do-have-to-go-now" baffle design :) There are a lot of complex arrangements out there, even the original Maxim design did offer a veritable assault course for the gasses to travel - but don't forget that there's no substitute for cubic capacity, make it as big as you can.
how much clearance do I need between the projectile and baffle walls?
More clearance = less effective sound suppression
Less clearance = more likelyhood the projectile will strike the baffles and be deflected.

It's therefore a compromise between noise and accuracy, depends what's most important to you. I think for spudguns the best solution is to avoid this possibility completely by making a ported tube design as used in shotgun suppressors to make sure the wad doesn't interfere with the baffles:

Image
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Sat Jan 29, 2011 6:35 am

I've been using the ported tube design for a couple of years actually and I'm not impressed by it. Thanks for the drawing linuxexorcist but I could easily mill out any kind of design... whatever is most effective.
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jackssmirkingrevenge
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Sat Jan 29, 2011 3:32 pm

FighterAce wrote:I've been using the ported tube design for a couple of years actually and I'm not impressed by it.
Nothing wrong with it as long as you have multiple baffles and a large tube.
I could easily mill out any kind of design... whatever is most effective.
The first design you posted looks more like "I have a CNC milling machine and I'm showing off" as opposed to "I've done my research on the best possible way to deflect gasses".

Image

There are many baffle stack designs out there, from what I've seen you can't really point at one being dramatically more effective that any other.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Sat Jan 29, 2011 4:34 pm

jackssmirkingrevenge wrote: The first design you posted looks more like "I have a CNC milling machine and I'm showing off" as opposed to "I've done my research on the best possible way to deflect gasses".
Does it really sound like that?? I don't have a CNC but I want something as effective as possible. That picture is just one example of many...
And you really don't need a CNC... heck even a drill press would do... all you need is a length of aluminum bar. One hole down the center for the projectile and a series of drilled out "triangles" down the entire length of the baffle.
jackssmirkingrevenge wrote: you can't really point at one being dramatically more effective that any other.
Actually you can... maybe not dramatically, but certainly more effective.

You're right, I haven't done my homework... I can't do so many things at once... but I do know a lot from all those years watching nutnfancy's videos :D
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Sun Jan 30, 2011 3:38 am

http://www.silencertests.com/

;)

Remember though that what works for firearms doesn't necessarily work for pneumatics. I've seen rimfires and high powered commerial airguns in 0.22" (Daystate Air Ranger, Shinsung Career that sort of thing) fired with the same suppressors, and I can tell you that the powder burners were much quieter.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Sun Jan 30, 2011 4:33 am

have any of you guy's used a muzzle brake ? & if so did it reduce the recoil ????
also does the supresser's work for noise reduction ????
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Sun Jan 30, 2011 7:25 am

jackssmirkingrevenge wrote: Remember though that what works for firearms doesn't necessarily work for pneumatics.
Hence my question...
Would this kind of design be suitable for a pneumatic?
“The combined synergy of a man and rifle is matchless.
The steadiness of hand, the acuity of vision and finally
the art of knowing how to make the rifle an extension of the
body all equate to the ultimate synthesis of man and machine.”
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Crna Legija
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Sun Jan 30, 2011 8:06 am

for a pneumatic you cant beat volume just make it BIG
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Hotwired
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Sun Jan 30, 2011 5:52 pm

What works for firearms will work for hybrids much better than pneumatics.

Firearms are using a small volume of hot high pressure gas, the gas loses pressure simply by being allowed into an expansion chamber but then loses pressure again because its being cooled at the same time.

With pneumatics in the spudding category you're screwed on all points because the gases are in fact really cold already - as it expands down the barrel the temperature drops through the floor.

The other thing is pneumatics round here tend to use a MASSIVE volume of air (small ones are usually several hundred CCs, large ones several litres) and dump it all in one go. There is no subtle solution to muffling a large quantity of cold gas which is leaving your barrel at significant pressure.

Dainty little tubes as on a small calibre rifle are not going to do much.


I did have some success (as long as a slug was being fired) in changing the rather loud fairly sharp report from my cannon to a loud dampened "thump" with a heavily padded and externally as well as internally ported suppressor.

Depends on the effect you're after. Really quiet means a really large volume expansion chamber though.


*edited: completely mangled section, seemed to have started a sentence halfway through another sentence.
Last edited by Hotwired on Sun Jan 30, 2011 6:16 pm, edited 2 times in total.
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Sun Jan 30, 2011 6:00 pm

I have about 30cc of chamber volume and 130cc of barrel volume.... the chamber is pressurized to 50 bar, how many cubic centimeters do I have in the chamber at atmospheric pressure?

Just to get a rough idea how much volume I need for the suppressor...
“The combined synergy of a man and rifle is matchless.
The steadiness of hand, the acuity of vision and finally
the art of knowing how to make the rifle an extension of the
body all equate to the ultimate synthesis of man and machine.”
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Hotwired
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Sun Jan 30, 2011 6:02 pm

Well 1 bar is roughly 1 atmosphere of pressure.

So multiply by 50 = 1500 cc / 1.5 litres :wink:
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Sun Jan 30, 2011 6:12 pm

auspud wrote:have any of you guy's used a muzzle brake ?
Yes.
if so did it reduce the recoil ????
Yes......Huge reduction in recoil!
does the supresser's work for noise reduction ????
Suppressors ARE for noise reduction. They are not muzzle brakes.
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linuxexorcist
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Sun Jan 30, 2011 8:11 pm

Quick question: has anyone tried using wipes in an air rifle suppressor?
i know firearm suppressors don't use them to reduce maintanence requirements, but they could be helpful in a less wear-and-tear situation like an airgun

Wipes are inner dividers intended to touch the bullet as it passes through the suppressor, and are typically made of rubber, plastic or foam. Each wipe may either have a hole drilled in it before use, a pattern stamped into its surface at the point where the bullet will strike it, or it may simply be punched through by the bullet. Wipes typically last for a small number of firings (perhaps no more than five) before their performance is significantly degraded. While many suppressors used wipes in the Vietnam War era, most modern suppressors do not use them to minimize disassembly and parts replacement.
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