custom suppressor for small calibres

[jackssmirkingrevenge]

I just wanted to share this design I'm making for a friend's 0.22" Shinsung Career 707 air rifle. This airgun puts out a powerful blast of air that has been known to tear apart lesser commercially available silencers. For this reason, the construction I'm using is fairly massive and heavy - weight being a less important consideration that overal strength.

The baffle array is first assembled using various spacers, with the washers on a steel rod to ensure correct alignment, and secured with quick setting epoxy. The assembly is then wrapped in duct tape and then secured in the main tube with epoxy, fixing the washers in place and adding extra srength to the PVC tube. The muzzle end is then sealed off, providing a large final expansion chamber with an 8mm hole at the exit.

Pictures show two views of the baffle array and a diagram of the completed suppressor.

[mopherman]

wow, that sure is purty. Looks like it must have been a biotch to line up properly.how did you make sure the holes lined up?

[jackssmirkingrevenge]

how did you make sure the holes lined up?

very easily, when I glued everything together all the parts were threaded through with a dead straight 6mm steel rod (laser printer cartridges are a good source ) so there was no chance of misalignment.

[Zen///]

WHOA!!!

I saw a diagram of a surpressor on wikipedia and it has the expansion chamber before the baffles, but meh, yours looks kewler.

[VH_man]

hahahahaha any chance of getting one of those silencers in .40 cal? dang... i think i might have to re-create that.........

[jackssmirkingrevenge]

Have a look around your hardware store - what you want is washers with a hole a few mm wider than your projectile, and with an outer diameter as close to your silencer tube inner diameter as possible. In my case there was only 3mm difference and I filled the gap with epoxy. Of course if you can find washers that fit exactly it's better, or you can even cut your own baffles from balsa wood sheet or similar.

Note however that this will only work for projectiles that fly straight, ie tight fitting spheres like airsoft or steel BBs, or elongated projectiles fired from a rifled barrel. For other types of projectiles that are unstable in flight you need a perforated tube.

[VH_man]

how about a blowgun dart? and i have an idea for seperators that should work great. hahahaha the gun isnt even built and im inventing accesories......

for the seperators, im going to use.... CRAFT FOAM........ (and some of those PVC tubes like you had just for strenght.......

i feel like the downfall of all my past supressors has been the fact that the PVC acted as an echo chamber/resonator and actually made the gun louder, no matter how i built the silencer.

ive got a great idea for this one though. Im building this gun to be the kind of thing you hand down to people as a "this was my toy, now its yours". aka it will be built well, and built to last. the silencer will not be any different.

[jackssmirkingrevenge]

blowgun darts are made to fly straight from a smoothbore barrel so you should be fine - I'd leave at least 3mm difference between the baffle hole diamter and projectile diameter though. The drilled out sections of PVC tube as separators have a dual function, not only do they add strength but they also conspire with the baffles to create more turbulence, which makes the suppressor more effective.

[VH_man]

ohh good point. i remember my first supressor for a spud gun... it was for the Barret 14mm. i fired it the first time and the supressor detonated. it was made out of a toilet paper tube and peices of cardboard. it LOOKED like it would work, and it worked on my airsoft gun. potato gun made the thing turn into peices.....

I just found a chunk of DWV 2 inch pipe.... perfect for supressor use.

and you said turbulence is a good thing.......... what if i drilled random holes all over my seperators? and put wire mesh in random places. mabey even filled the thing with steel wool/cotton. gah ill just have to try it.

[Zen///]

Steel wool is better for combustions, while for punematics cotton or something of the like is good.

[Novacastrian]

Have you tested this design yet JSR? If so a guess at decibel reduction would be interesting- i know you are not db meter, a guess is fine.

[jackssmirkingrevenge]

This is the second unit of this type that I'm making - the previous one was similar in construction and dimensions and had a dramatic effect on the sound signature - it went from a ear-splitting muzzle crack to a practically silent shot, the sound of the hammer hitting the valve was the most audible noise. In fact it was the effectiveness of the said design that prompted the original owner's mate to commision one for his own rifle

Ironically, such rifles are easier to silence than the creations we fabricate, because they use a tiny volume of high pressure air as opposed to our large volumes of relatively low pressure air.

[Zen///]

What pressure do real air guns operate at? What volume?

[windshrike]

Most PCP airgun's using HPA operate at around 3000 psi, unregulated, with a hammer valve to fire the pellet. Nice silencer Jack, can't wait to hear how this turns out.

[jackssmirkingrevenge]

What pressure do real air guns operate at? What volume?

My Daystate is filled to 3350 psi and has a relatively small chamber (the tube under the barrel) but will give 60 good shots (at full 28 ft/lbs power - lowering it to half the power gives much more) per fill, so very little volume is released every time.