Machined cartridge question

[Dave_424]

Hello, Im thinking about making a cartridge that is fully machined from prorably brass or 303 stainless steel

Im wondering weather to go with a high pressure pneumatic cartridge (Prorably a coaxail) or a high mix hybrid but I dont really want to mess around with burst disks and fuelling etc. But would yeild very good results.

After building the cartridge, I would then machine a bolt action basically an exact copy of a firearm action.

Let me know what you think, I have access to 3500psi and a full machine shop.

Dave

[Demon]

I hope you have access to cnc machines if you want to make enough cartridges ...

[Dave_424]

Nope, no CNC for me, I am quite used to churning out multiple parts.

I would first make 1 prototype, then make prorably 5 cartridges.

I think Ive decided on a high pressure coaxail with a homemade pilot valve.

Dave

[Gun Freak]

I would first make 1 prototype, then make prorably 5 cartridges.

It's spelled "probably". Just telling you, because you spelled it like that in the original post and in your reply. 8)

[Dave_424]

I always seem to spell it wrong

Dave

[john bunsenburner]

Will you be using shraders as fill valves?

[Dave_424]

I dont think I will, I will use a threaded 0-ring sealed fitting, I think I will fill through the barrel and have a light spring behiend the piston.

Im thinking of making them the same size as a 12 bore/gauge shotgun so I can test them as soon as I make them. Shooting maybe machined plastic slugs or some kind of saboted round

Dave

[Gun Freak]

How are you going to fill it through the barrel? And what is your exhaust valve (I figure you're using a piston)?

[Dave_424]

As you fill through the barrel, the air pushes the piston back and after filling, the spring returns the seal back to the seal face.

Im still pondering over weather it will actually happen but it is good to think about.

I do have a big piece of 30mm steel 20mm long.

Dave

[john bunsenburner]

I never considered that option! Haha, sounds great, especially because a filling station is easily built.

[Gun Freak]

Yeah that sounds good. Will there be a schrader in the back for exhaust?

[Dave_424]

It will be a schrader in function. A machined poppet style valve in the rear, functioning like a schrader pilot with a delrin seal.

Dave

[Gun Freak]

Oh ok cool. Can't wait to see the gun...

[jackssmirkingrevenge]

With machining facilities you could easily replicate the Brocock Predator pneumatic cartridge rifle, and with an exhaust valve coaxial design and HPA you would certainly do better in terms of performance.

Also, since you're opting for bolt action, you'd have none of the blowback worries I had with my prototypes

[Dave_424]

Im not really sure what to do, I doubt I will get the power that I want from the size of cartridge Im planning on using. (around the .50 BMG size)

So my thoughts have turned to a high mix hybrid. Using the shape of a firearm cartridge, could I use some kind of piston?

EDIT: Modelling roughly the same size cartridge as a .50 I can roughly get a 100 grain bullet at 800+ fps for about 140 foot pounds.

However if Im going hybrid, should i just say screw it and go big?

Dave