I'll bet it's a 30/30. If it'll chamber a 30/30 case it is a 30/30. The 30/30 won't chamber in a 30 Rem chamber and it won't chamber in a 303 Savage chamber, so you don't risk a thing by trying. If you were close to Prineville we'd find out in a hurry because I have all of those suspects so we'd very soon find which case slides into the chamber.
