Cartridge help.

[warhead052]

I have been asked to make a hybrid howitzer for airsoft/paintball, (I know, but they wanted sound and shell ejection) and I would like some help with this. Considering they want a 2.5x mix at a minimum, would a real howitzer shell (unloaded of course) be able to handle the pressures? My overall question is, how should I go about making this? Burst disk hybrid, unbalanced piston (for shell ejection)?

[jackssmirkingrevenge]

bit more than you can chew?

[warhead052]

Not entirely. I just want to make sure that I can get this done without anyone getting hurt from the resulting product. The captain of the team who wants me to build this is a friend who I have known for a while and has offered his machines if needed (lathe, mill, welding equipment, and a giant assortment of tools and around 7 air compressors...). So, any suggestions as to what I should do?

[jackssmirkingrevenge]

lathe, mill, welding equipment, and a giant assortment of tools

now you're talking what's the budget?

[Labtecpower]

Make a design? with equipment like that you should be able to make something nice

@jack; any money yet?

[warhead052]

I believe $800, plus what ever bits of scrap and other various parts at his house. (His land is covered in scrap metal from his grand father so we kind of have that part covered)

Edit, just saw your post Lab, I don't have any designs yet, except for a HGDT model of a burst disk at 5x with a disk failure at 100 psi.

[Labtecpower]

What calibre are you looking after?

[warhead052]

2 inch bore, hopefully. Like I said, I would love to use an actual howitzer shell for the chamber to add realism, but if it can't handle the pressure then oh well. I will be shooting buckshot loads of 1,000+ airsoft bb's and 500+ paintballs. Maybe nerf vortex rockets at times, if they don't get shredded to pieces mid flight.

[Labtecpower]

Can you cut threads on the lathe?
If yes, you could make your own burst disk holders.

For an end cap I would go for machined and welded steel, with threads for filling valve and spark plug.

[warhead052]

This will be my first time on a lathe, so I would probably make a few 5:10 scale models before I actually make the real thing. I will see about the threading.

Any suggestions on ignition?

[Labtecpower]

capacitor/ignition coil circuit works fine for me, but maybe you want something with a lower recharge time.

The system hotwired made would be very nice

[Gun Freak]

I'd give the plans to someone who knows what they're doing on the lathe and let then turn it, so you don't screw it up. Other than that, I don't have any good input. I'm a pneub

[Zeus]

Does it <i>need</i> to be a cartridge? It would be exceedingly cheaper to make a piston hybrid, SB15 and MrC will say the rate of fire is very agreeable.

If you have the chamber fixed, and have a camlock to the barrel which is free floating, then you'd be able to preload the ammo in PVC cartridges.

Much simpler, the rate of fire will be better, and you don't have to design something new. Not to mention it will be far more versatile.

[evanmcorleytv]

Hey warhead.. I wouldn't honestly expect a 14 year old to know how to build a hybrid, shell ejecting mortar.. but since we live 45 minutes apart, maybe I can help? FIRST OFF, you should make it pneumatic. and. only. pneumatic. I've been doing this for 4 years.. and I can honestly tell you that PNEUMATIC IS THE WAY TO GO!! Not to mention that fact that airsoft/paintball fields don't like combustible gasses.. if you need help call me up, and we can maybe even get together sometime!! I have a mauler that needs a cannon after all!!

[Gun Freak]

First off, age has nothing to do with it. Warhead has gained quite a bit of knowledge in his time here. I think he has the right knowledge to make it.
Second, about the pneumatic idea... I agree