SpudFiles

I've designed a rifle that uses cartridges like JSR's pen gun and Spudchucker's 5mm. It will eject them like one of the guns on here, i cant find it ..... and this will hopefully be 6mm. cartridge will hold bout 3-5 . they will be pumped up to around 150-200psi if i make them out of copper and if i make them out of pvc they'll running around the 150psi mark if i do make it out of pvc (which i probably will ) it will be 15mm pipe.

any suggestions, plans, diagrams go for it ill get mine up tonight or tomorrow .

I'd go for copper, i wouldn't trust PVC at those levels...

Ejecting cartridges will get pretty banged up, a single flaw could have the PVC fail

My suggestion is that if you use pvc, remember that the pvc will swell/ bulge a little when pressure is put into it.

Metal might do the same depending on how much pressure and how thick the shell is.

Also if it doesn't bulge a little the recoil ,friction and pressure will kick it out of the chamber faster.(maybe before the projectile exits)

To counter this effect and get a better seal between cartridge and barrel you could add a thinner short tube protruding from the case.

That way when it fires the portion closest to the barrel will bulge a little giving a temporary seal like in firearm shell casings.

Again take a look at this project, it's basically the same idea.

yea it is, but if i use this with pvc and pressures like 100-120psi it shouldnt be so bad, copper is so damn expensive over here it ridiculess.



whooot whoot 1 red star

I used PVC too ;p Also I don't think 100-200 psi is going to cut it for a cartridge which ejects as well, when using small calibres and low volumes you really need to up the pressure.

jackssmirkingrevenge wrote:Again take a look at this project, it's basically the same idea.

I meant to suggest that you check with the pro on burst disk cartriges in my first reply.

BTW a long time ago I saw advertised the smallest revolver ever they claimed. it was a tiny revolver on a key chain that had reloadable pneumatic shells and claimed it went off with a bang.
I was came with a tiny pump was coin sized and they ran out of them Just wondered if anyone else knew of them?

THUNDERLORD wrote:BTW a long time ago I saw advertised the smallest revolver ever they claimed. it was a tiny revolver on a key chain that had reloadable pneumatic shells and claimed it went off with a bang.
I was came with a tiny pump was coin sized and they ran out of them Just wondered if anyone else knew of them?

Not a revolver but I think you mean this one?

@ JSR I may be confused With that one. It was a long time ago. I thought there was a revolver similar and they said the same thing, it had been imported from some obscure location and they had lost contact with the seller.

WOW, that one says 3000psi!!! Actually I did see this one years ago and It made me daydream about building one the same size using a .177 barrel and a muzzleloader nipple (#11 percussion cap) Hope I'm not breaking the rules too bad. But that would be one way to own something similar (but less impressive). Thanks for the link!!!

@ajdevi92 ,sorry for going off for my own info but it's still on topic I think.
Please keep us updated w/ your project.
Thanks and BTW, You have some great designs and videos!!!

ajdevi92 wrote: any suggestions, plans, diagrams go for it ill get mine up tonight or tomorrow .

Do a Google Patents Search on John M. Browning, John C. Garand, and Hiram S. Maxim.
That should give you a good starting position.

I don’t recommend pure, un-delayed, blowback; it’ll probably be able to kick out the brass, but it won’t offer much downrange power.
If you go with blowback you either need to run high pressure or have a delay mechanism; and the only ones I can think of that would work in this application are Blish lock, toggle delay (think P.08 Luger), or some form of lever or friction delay.

Although at the lower pressures your not going to have enough power to both propel the projectile and open a delayed bolt…
I say go with copper and high pressure cartridges, and try gas delayed blowback or gas operation.

Thanks for mentioning my gun someone asked if it was posible to use 3-5 of these ask carts in a gun was that you?
EDIT: I got my name changed.
EDIT #2: Maybe instead of letting the carts falling to the dents maybe you could have a bag to catch the carts?