full-auto breech :D

[jackssmirkingrevenge]

Fair point clide, looks like I misinterpreted your idea.

wouldn't a simple way to limit the rpm's (and therefore allow the ammo to fall into place more easily), be just to reduce the flow?

Naturally i've tried this - the problem is that since the system isn't airtight, the air will simply leak past the bolt - I've tried varying the flow as much as I could but there are only two results, either it cycles very fast or doesn't at all.

[TwitchTheAussie]

I congratulate you jack. You always amaze me

[jackssmirkingrevenge]

Thanks, but you should wait till I actually make something that works hehe

[VH_man]

I know this is an old topic, but why start a new one, eh?

I was looking at this bolt system and thinking of recreating it for a Pellet gun but then i saw your actual results............

what if you:

1. Placed something on the bolt that stopped it from moving to far......
2. increased the mass of the bolt

the way it seems to me, this actually might have some potential if the bolt is heavy. the momentum would keep the bolt in the foward position for long enough to let the BB/Pellet actually come out and stay rearward long enough to build up some serious pressure

anyway, You might see some revised things on this breech system...... i have my own ideas on how to make it work. they wont be as pretty as this though........

[jackssmirkingrevenge]

Good suggestions that might work, I could put a pin through the bolt to reduce its travel and fill it with lead (or mercury ) - unfortunately I can't try them out for myself as the prototype had been cut up. I might be persuaded to give it another go however. The heavier bolt idea for example is used in submachineguns to reduce the rate of fire.

[spudgunnerwryyyyy]

Wouldnt a really heavy bolt also increase wear on the gun, You know way more than me just something to throw out on the table.

[jackssmirkingrevenge]

Wouldnt a really heavy bolt also increase wear on the gun, You know way more than me just something to throw out on the table.

That would certainly be one my concerns, whatever you're using as a bolt stop would need some sort of rubber bumper in order to mitigate the repeated impact. I've got a custom silencer on the workbench at the moment but I might give this a try later on - the theory is certainly sound, maybe I abandoned the idea too soon.

[jackssmirkingrevenge]

I think I did shelve this idea too quickly without looking at ways to improve it, might just be worth giving it another go. I've incorporated some of the suggestions on this thread, namely a bolt stop that will prevent the bolt travelling far down the barrel. Also, I've decided to make it within a threaded coupling so I can take it apart and service/modify the bolt. I predict that I'll be able to use a fairly weak spring, that should lower the cyclic rate enough to allow ammunition to load reliably.

[ALIHISGREAT]

A double post?!? i thought better of you JSR

thats an interesting design which i look foreward to seeing built *hint hint*

[POLAND_SPUD]

Is a bolt really needed ?

I think this might work better than a blow forward breech design... you only have to make chamber as small as possible and use o-rings so that only one round is fired per 'shot'

JSR don't mention that dead space - it's just a rough sketch ok?;

(the flow control valve is to adjust the ROF)

so.....would this work ?

[jackssmirkingrevenge]

A double post?!? i thought better of you JSR

Oh come on, you know I'm not a post whore, and if I had just edited the previous post no one would have noticed ;p

POLAND_SPUD, what you're proposing is essentially similar to this design, only the latter uses an airflow driven paddle to interrupt the flow of ammunition per shot (though not preventing the air from getting into the chamber).

[ALIHISGREAT]

Oh come on, you know I'm not a post whore, and if I had just edited the previous post no one would have noticed ;p

yeah you probably have enough spudbux to buy a small country.

[POLAND_SPUD]

Yes JSR I've seen that gun before.... but is that paddle really needed ? if the magazine tube has ID as close to the caliber of the ammo as possible the flow of air would act on the rest of ammo in the magazine for a fraction of second - keepping it out of the barrel (and blocking the air from entering the magazine tube and therefore limiting dead space

What are advantages of this blow forward design over this design ?

[jackssmirkingrevenge]

For me the advantage is that you're not limited to a spring loaded mag, you can just feed from a hopper like paintball markers do.

[Flash]

I think there would also be a problem of some air traveling inside the magezine/hopper instead of the barrel, if a bolt isn't used.