Ive put the link to my diagram up at the top.

Do you care if I replicate your gun? Do you think it can shoot at 500-600 fps?

Do you just use a diaphragm or you use some kind of piston and do you have a spring behind it? Doesnt the barrel cut into the piston/diaphragm?

Hey dude sweet cannon!! Where did you get a compressor like that and do you think it would be possible to make it fully portable?

I decided I am going pneumatic. I have drawn a diagram on a piece of paper but I dont have a printer so as soon as I get to draw one in paint I will post it.

But still I think combustion would so much cooler, it would have a kick back and all that but yea I am making it air powered. Now I have to decide whether I am going to give piston a try again because if I do coaxile I wont be able to properly fit it.

joannaardway-Thank you alot for all the information. I am leaning more towards penumatics because of low cost. Ive found a portable 200 psi air compressor that runs off a motorcylcle battery and I could put all that into the cannon so it would be somewhat semi-auto. risto-You do have a point there b...

Well I just watched a video at bcvids on how to make a barrel sealing valve and It looks reletively simple and its pretty cheap. The only proble is how am I going to fit all that in the case.

^Hey I got the Idea from your Icon. Thanks! Well the only major difference that I can see between Pneumatic and Combustion is that pneumatic is usualy much more powerful. But Burntlatke states that combustion can also be as powerful. I am going with the golf ball diameter. I think it would be a litl...

I was browsing these forums the other day and I saw some ones picture, it has Linux holding Quake 3 rocket launcher. So I came up with an idea to make a replica of Quake 3 spudgun. I am planning on making the spud gun itself and then making a plywood casing that looks just like the rocket launcher a...