This may be simply stupid of me, given I have very little mechanical or legal knowledge of the subject, but I'm interested in starting a firearm project and was wondering whether it would be possible to convert a cx4 storm into a bullpup (not with the magazine through the grip like it already does but behind the grip). Basically my question is whether that is even mechanically possible and if so, would it be an expensive venture to have it done by a gunsmith? Would it be legal to basically make my own polymer "kit" or body for it as well? Also what is the minimum length for a civilian legal rifle? I'm aiming to create the most compact civilian legal rifle possible. Thanks for any replies!