Zastava says the Mini-Mauser mag box is 2 19/64 (2.297)long. Pictures of the action seen on Gun Broker, etc. show about 1/4 inch between the rear of the box and the front of the trigger housing. Maybe it could be lengthened that much.

http://www.zastava-arms.co.rs/images/civilni/lovacki_karabini/14654-14653-14650.htm

Bruce