Richeydale67

Hello, I buddy of mine just gifted me an old Sabatti Forest .20-76 over 7x57R. They are so rare here in the states I took it to 3 different gun shops and they had no idea what to put in the bottom barrel. Everybody here is all about Glocks and AR's. Just took a little research and I found the 7x57 ammo. My question: Is 7x57 the same as 7x57 Mauser and .275 Rigby? The more I learn about these combo guns the more I like mine. As far as I can tell it's an excellent survivalist piece.