I Built this model years ago (2005) with AutoCAD. I then converted it for use in Solidworks hence there is no history tree. I intended to make a paintball version of the P-90 and this was my first attempt at it. As I have no knowledge of how paintball guns work I took my best shot. There are some working internals of how I thought it might work. Measurements were taken off of a real P-90 but some of the surfaces are incorrect..