Dr meat201 wrote:
-Not Combustion
-Must shoot fairly far
-Semi auto/bolt (something that can be ready to shoot again fairly fast, my last one was a muzzleloader & took WAY too long to reload)
-Must be able to buy parts at Home Depot/Lowes
-Preferably below $60 MUST be below $80
-Can't have machined parts (I don't have a lathe or other ways of machining)
Only having made one cannon, you're not going to get decent semi-auto unless you have a CO2 reg, sprinkler valve and a portable bottle of CO2.
Sprinkler valves can be semi-auto but you need an air supply, not bike pump.
If you don't have an air compressor or CO2, you can't really do semi-auto.
Since it's your second, making a decent semi-auto under $80 would be hard.
So scrap semi-auto for starters.
Must shoot far? How far?
You want real distance, go golf balls. Or just use paintballs.
Breech loading will be easy, search this website for some ideas, don't rely on us to give you them, there are loads on this website.
So now that we have that settled, you either looking at a cannon like*:
<A HREF="
http://www.spudfiles.com/forums/viewtop ... 8">This</a>
Or
<A HREF="
http://www.spudfiles.com/forums/viewtop ... ">This.</a>
The second one can be made under $60US I would think, the first one could be more.
For your first pneumaitc keep it simple, most members who have built several haven't gone semi auto yet.
Also if your making a mag, it's harder then you think. If you have a verticle mag you need something to stop multiple projectiles getting shot at the same time, since the air can suck out more then one.
* I don't mean your restricted to that desgin, but more or less that is a similar setup you would use for a basic but powerful pneumatic.