SpudFiles

Whenever you can, simply use a tubemag.

POLAND_SPUD wrote:I doubt that double feeds have anything to do with the hopper... is there anything that stops bbs from entering the barrel?

I might have put an o-ring as a detent, don't remember

Question, Why not just buy a paintball hopper and modify it for your needs?
You can get them fairly cheap.

In my case these are for a small calibre so it wouldn't really be useful, but good idea for those using marbles.

psycix wrote:Whenever you can, simply use a tubemag.

As I mentioned in the original post, tube mags are limited by capacity - you'll never get the kind of long bursts one sees in belt fed machineguns.

I might have put an o-ring as a detent, don't remember

well yeah that was dumb but what about the other side of the T then?

if it's constructed teh way it should it's even more interesting...
the hopper is sealed right ?? if so then possibly the tube doesn't offer enough fit and too much air enters the hopper... then it exits the same way it got in carrying bbs with it

EDIT
I tested the idea in Phun... while I couldn't reliably replicate what I wanted to test in the first place (as I couldn't simulate the effect that air has on bbs) I came up with this

a piston with a spring behind it would oscillate with each shot (as some air passes into the hopper.. here it's simulated with a basic motor)

I don't know how accurate phun is but I simulated several different configs of a simple hopper and BBs did jam

psycix wrote:Whenever you can, simply use a tubemag.

I've been thinking about this, the most annoying thing about tube magazines is that they need a lot of length, especially with the spring taking a considerable amount of space.

I came up with this variant that might just do the trick though. The spring is eliminated, as the BBs are pushed along by the air coming from the valve, and you have a magazine that's twice the length of the barrel. Assuming 4.5mm BBs, this means that using a reasonably sized 50cm barrel, you could fit well over 200 BBs, when your average "real" submachinegun fits around one tenth of that. If that still isn't enough you could always increase the number of "coils".

I've had similar thoughts about the rotor design, maybe something closer to a vortex strafer with a rotor in it. Perhaps something where the BB could be trapped/pinched between the rotor and O ring while pressure builds up.

As for the above picture, what do you think about using a 1/4" coiled air hose as a magazine?

The rotor could easily be electrically powered for independetly variable rate of fire, but that's too much of an added complication in my book.

kozak6 wrote:As for the above picture, what do you think about using a 1/4" coiled air hose as a magazine?

Dewey suggested that here, if you could find suitable hose coiled suitably tightly, why not.

I think you should connect the top of the hopper to the piston to make sure it works.
I mean..The top of the hopper would be the piston, with a rod to plug the feedhole.

I've used some tube magazines on a paintball marker, but ended up using an elastic band pulling the piston back instead of of a spring. That adds alot of capacity.
And well it easily keeps up with high ROF, much more reliable than a simple hopper.

I've decided to give the tube mag a try:



It's currently sealed up and swimming in slowly solidifying epoxy, I'll give it a whirl tomorrow at 50-100 psi and see what happens