The Offcial Machinist Thread: Revised 01/04/2014

[jackssmirkingrevenge]

Ah, finally! Nice work

Some advice on baffle design, the holes should be bigger... did you drill them or mill them out?

How exactly does a gas blow-back airsoft gun works?

http://arniesairsoft.co.uk/?filnavn=/ar ... sagbb.html

[wyz2285]

I drilled them with my mill.
These are 6mm holes, the bullet pass is 8mm, I didn't want the holes be bigger than that. But I could drill 2 more on each stage.
Both design looks complicated and wast gas, I'm doing my own

[jackssmirkingrevenge]

These are 6mm holes, the bullet pass is 8mm, I didn't want the holes be bigger than that. But I could drill 2 more on each stage.

They should be bigger than the hole for the bullet. The idea is to create a swirling vortex of gas which then makes a barrier making it more difficult for the following gas flow to exit.

[wyz2285]

What if I drill 2 more holes? 10mm holes may be larger than the shank

[jackssmirkingrevenge]

Either bigger hole, or more smaller holes

[wyz2285]

I drilled 2 more on each baffles, didn't notice too much difference through. Anyway, I'm happy with it

[Gun Freak]

Both designs look complicated and waste gas, I'm doing my own

I like the way you think

[jackssmirkingrevenge]

I like the way you think

*cough*

[wyz2285]

For this first time I proved that a suppressor made by myself really works
[youtube][/youtube]

[jackssmirkingrevenge]

Nice...as you say though, with an AEG most of the noise comes from the motor and gearbox. You could have done a series of noise measurements with no BBs and your finger over the muzzle.

Were you shooting BBs after all? If no, then the test is invalid because the BB has a "blocking" effect which encourages turbulence in the suppressor. If yes, then you need to be shooting at a soft pillow or something which absorbs the sound, or into the air, otherwise projectile impact noise is interfering with your measurements.

Have a look at this Silencerco test:

[youtube][/youtube]

Note how they rest the muzzle on the post so it is always in the same position relative to the microphone.

[wyz2285]

Were you shooting BBs after all? If no, then the test is invalid because the BB has a "blocking" effect which encourages turbulence in the suppressor.

I thought so, I basically took all the shots to my bed I however also did some shots with no bbs, didn't notice the difference, perhaps the bullet passage is too large.

Note how they rest the muzzle on the post so it is always in the same position relative to the microphone.

I did that too, the distance between the muzzle and the microphone were always the same (not exactly, but not big enough to make a difference)

You could have done a series of noise measurements with no BBs and your finger over the muzzle.

I did try that, and to be honest the noise isn't much quieter than with the new suppressor, I forgot to record them through, should have thought about it

[jackssmirkingrevenge]

perhaps the bullet passage is too large

This is definitely a factor.

In my own experience, the difference in noise between having a 7.5mm port and 6.5mm port for a 5.5mm rifle is extremely noticable. If you're confident that everything is centered, then you don't need a lot of clearance.

[wyz2285]

If you're confident that everything is centered, then you don't need a lot of clearance.

I'm very confident, as the parts need a push to get in.
But I only have 6mm and 8mm drills, so for a 6mm bb 8mm drill was my only choice (considering the inner barrel isn't as long as the outer barrel so the bb will be traveling in a 9mm tube before entering the suppressor I'm not confident with the trajectory of the bb)

[jackssmirkingrevenge]

You could always extend the inner barrel and perforate the end of it.



Again though, this being an AEG, it's going to sound like a sewing machine no matter what you hang off the muzzle...

[bookyle]

Again though, this being an AEG, it's going to sound like a sewing machine no matter what you hang off the muzzle...

So true. I have seem people put more than 1k into their aeg upgrading mosfet, gears and what not and when I fired it, it sounded like a cheap toy, even though the external is beefed up.