Chamber to Barrel question

[battlelava]

Ive been looking into making a breech loading potato gun and i wanted it to look like a WW2 howitzer. But when i was looking at a self contained "shell" (combustion cartridges) i came across this http://www.spudfiles.com/forums/how-to- ... 22301.html and it has gotten me confused on if i would still need a chamber
Any help would be appreciated on clearing this up

[jackssmirkingrevenge]

Do you mean my use of the same tube as both barrel and chamber?

Basically you'd need two tubes, one open on both ends which is you barrel, and another, closed on one end and with the projectile jammed in the other, is your cartridge.

Some links which might be of interest:

http://www.spudfiles.com/forums/combust ... 10402.html

http://www.spudfiles.com/forums/cartrid ... 20150.html