It could just of been civilian tech used for war, like a nail gun but one that originally fired M12 bolts, now it fires rockets.
As long as the barrell and breach are the right size it could be done i guess.
Everyone has a purpose, just so happens mine is more of an example to others of what NOT to do.
I know it's time to go to bed when the last post in every thread has been written by me.
Hooobit, nothing more nothing less.