Buying new plywood just to break it is a luxury I can't afford.

And then the contest moved too close to Punkin Chunkin time!

Using a 50 foot barrel and 40 foot ammo, I guarantee I can break every board that is less than 40 feet away from my barrel (80 boards if point blank).

Using a shaped charge ...

Rifling: For ammo stability there is only one answer.

Very cool rolling tripod mount, what max angles for firing and travel? I plan to do something similar while mounting a cylinder in the third leg but had not considered adding an elevator till now. currently I use a 4 wheel cart with wheels that ...

Calling BS?!? This is a contest, of course I intend to back up what I say.

But no, I will not mention how.
http://atomicjew.home.comcast.net/~atomicjew/ben_0011.jpg
0.015" Steel flashing. 140 psi. Target distance 80 feet.
Edited: I corrected the thickness of flashing, obviously its .015 not .15 ...

500 psi chamber to a 2 inch barrel :?
and only 10 feet of barrel? :shock:
are you designing a mortar? I can out penetrate that with 175 psi . . .
This config has supports but no need for sleeves to shoot a mile.
http://atomicjew.home.comcast.net/~atomicjew/nov_0121.jpg

I have done years of ...