Withover 110 years of history there are quite a few calibers.30-30 win(30WCF),32 win special(32WCF),25-35win,38-55win,307 win,356win,375win,444marlin,32-40 win.Hope this helps
By the serial number letters BB ahead of your serial number,it sounds to me as if you have a Winchester model 1894 XTR big bore.These were chambered for the .307Win,.356Win,and .375Win,cartridges from 1983-1998.The .375 Win cartridge was only available from 1983-1987.Later they added the 444 Marlin to this line.Being that your rifle is marked with the XTR marking,this dates your rifle from 1983-1989.