an unmodified selected caliber handgun having a barrel receiving {HEAD ~ cavity} with {TAIL ~ a mounting surface} for receiving a live ammunition firing barrel 
with
an unmodified selected caliber handgun having a barrel receiving { HEAD ~ cavity } with { TAIL ~ a mounting surface } for receiving a live ammunition firing barrel
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH