Airsoft machine gun

[mako]

Hey, guys. I've been reading around for a while, gleaning ideas from the conversations.

I'm an avid airsofter, and want to make my own guns. I recently built a pretty good bolt action sniper rifle. I now want to make a machine gun.

The idea I wish to propound(I think I got that right), is for an air powered airsoft gun. The idea is to have a revolving cylinder, with many holes for BB's around the edge. A pressurised hose would be against one side, across from the barrel, and the cylinder would be spun. The air would fire BB's as the hole passed in front of the hose. The solid spaces in between the BB chambers would prevent too much air waste from the constantly pressurised hose. I hope this would be more air efficient than a vortex gun, as I want this to work in an airsoft game.

Thoughts on how practical this would be?
Sorry about the lack of pictures to illustrate the idea, but its too late for that kind of mental effort. If there's any response to this post, I'll put up some pictures in the morning.

[jackssmirkingrevenge]

I thought about using a "rotor" in the past:



and an air powered version:



The above would likely not work very well because of the interrupted flow of air, however if you use an external power source like an electric motor you should be fine.

[mako]

That's actually a lot better than mine. You said that the "above would likely not work very well". Did you mean the one that used the airflow to turn the cylinder?

Another problem with it would be that the ROF would be directly related to the pressure and therefore also with the FPS. Probably not a problem with most BBMG's, but it might be a problem with airsoft. The FPS needs to be low enough that it won't cause injury, but high enough to get a good range. The first idea, though, the one with the electric motor looks really cool.

[mako]

Also, you said you'd thought about it. Did you ever try to build one or know someone who did? I've not run across one like that before.

[cammyd32]

A good (and probably easier) way to achieve what you want would probably be to have a standard vortex with a detent and robustly made hop up. With a finely tuned barrel length it would probably work a lot more reliably than the idea you suggested, here is a good example of someone who did something like it: http://www.spudfiles.com/forums/adjusta ... 22834.html
Without 1000 odd quids worth of lathe and machining equipment what your suggesting would probably be hard to make accurately enough to work, hence why no-one has really tried it out before

[mako]

@cammyd32, I don't know about the vortex idea, but I kind of suspected that I'd need some machining tools to make my idea work well. Know anybody whose actually used a vortex in an airsoft game?

[cammyd32]

sometimes you don't even need to use a vortex block: http://www.youtube.com/watch?v=ME1BcEcBD9I
Quite a few people have made vortexes for airsoft before, whether they have actually used them for it is a different matter completely, the practicality of a continuous stream bbmg is quite limited given the air needed to agitate and 'reload' the bb's it often never goes further than a once use firearm, if you had somewhere that refilled paintball tanks and if you got a decent reg then you could probably make something like this:

[mako]

Yeah, that was the limitation to all of the ones I've run across.
Any thoughts on QEV's for full auto? Would one work with a homemade PVC compressed air tank at 100 PSI?

[jackssmirkingrevenge]

Also, you said you'd thought about it. Did you ever try to build one or know someone who did? I've not run across one like that before.

I tried making a combination valve-breech rotating coaxially with the barrel, didn't work out too well.

If you want this for airsoft, be careful - you will be amazed at what the effects of concentrated fire can be.

This was done with plastic BBs, albeit at 800 psi:

[youtube][/youtube]

[mako]

@JSR
Was the video done with one with a cylinder or a standard vortex gun?
I've seen a lot of your posts and the vid looks familiar.
As to the damage super high Rate of Fire can do, yeah, I know!
I'd have a minimum engagement distance if I built one. My stock JG T3-K3 does around 380 FPS, and maybe 5 rounds per second, and a friend borrowed it for a game. Stitched about 10 rounds from my knee, up my side to the back of my neck. That hurt like #$%. I cannot imagine what the rate of fire from a vortex gun would do.

[jackssmirkingrevenge]

Just a simple tube full of BBs and a rubber breech seal in an effort to keep the rate of fire down.

http://www.spudfiles.com/forums/hpa-air ... 21457.html

[mako]

Impressive performance. 8) What kind of air efficiency did you get? I assume you are hooked up to a compressor? One of the major problems I have with the vortexes is the wasted air. Can't have a stationary machine gun under the conditions I play.

BTW, am I posting too much for a newbie? If so, shut me up, quick.

[jackssmirkingrevenge]

I was running that off a paintball tank. What's the possibility of you getting one of those? I take it you're on a fairly limited budget.

A cheaper alternative is to get yourself a small fire extinguisher as an air chamber and fill it using a fridge compressor to say 600 psi and you will have more than enough air for an airsoft game.

Obviously 600 psi will give you too much power to be used safely for airsoft in a normal setup, you could use a regulator to bring it down but that involves quite a bit of expense, a good alternative would be to limit the flow of your valve (say have it feed through a 1mm bore), this brings power down to safe levels and greatly reduced the rate of consumption.

[mako]

You're pretty discerning. Yeah, not exactly limited, but what I do have goes to airsoft guns I know will work.
I have a record of getting in over my head, so I try to keep my projects low cost. The paint ball tank isn't out side my cost range, but I'd like to be able to keep the pressures low enough to use PVC. How hard is it to work with the metals necessary for that kind of pressure?

[jackssmirkingrevenge]

If you're using standard fittings, no hard work at all.

It's only "hard" when you're the sort of bodger who thinks a badly designed epoxy fitting will take 800 psi