3 inch barrel and chamber

[conrad]

Well I just joined but I've been making spud guns for a few years now. Now on to the question.

I'm in the process of planing and building a Carl Gustav rocket launcher spud gun. My question is that if I use a 12" x 3" chamber with propane and the barrel also has a 3" diameter, would this actually fire a projectile?
What If a reducer was added in the middle? I've only ever built guns with barrels smaller then the chamber.

I'm not looking for great distance on the projectile, this is going to be used for airsoft, so approximately 100 to 200 yards is the distance I need.

[iamthewalrus]

it should work, cuz DR's basket ball cannon looks liek its one size and it works, but i could be misstaken

[CS]

Ya it should work. I think it also helps if inbetween the chamber and the barrel you step it down to a 1 1/2 or 2 inches then back up to 3 inches. I dont even know if this is true and if it is i dont know the science behind it. I ve seen alot of people do this.

[luckythirteen13]

it will work. just put an all-thread bolt through the pipe so that the projectile always sits in the same place when loaded. this will also give you a .8:1 c:b ratio

[iamthewalrus]

pimpman if u did that wouldnt it just restrict flow shotting it less far??

[CS]

Thats what i was kinda thinking but ive heard that they do that to get all the pressure to focus on one point instead of going on the sides. But i may not be right .

[conrad]

Thanks all you guys. I'll post up some pics as the project gets underway.

[luckythirteen13]

if you put a restriction in it, it wont focus the power, it will just choke air flow. once the air makes its way past the restriction, it will not focus right down the center, it will expand out to the sides, then go up the barrel