First Combustion Rifle (Some Advice Needed)

[popomon]

lol thats awesome. (the poem) with your cannon dude, i would instead of having what i assume is the chamber as your stock, make it over under something like this
__________
| _________
| |_________
|___________|

thats a kinda dodgy drawing, but it outlines an over under. basically chamber is directly under the barrel, generally halves the length (sometimes, it does make it shorter though) and some say it looks better.

did you see the diagrams? I made a chamber and it is an over and under. ou have to look at both of them for before and after