I'm wondering if there may be an inexpensive rifle in 50bmg. Maybe like a ruger no1 in that caliber. I don't think there is so what if you could make a barrel chambered in 50 that would link up with a single shot shotgun.You would have the trigger and hammer taken care of but could it hold up to theressure? A 12 gauge has alot of pressure,can it be done? Also is there a legal way of making a gun.