Very first one were 30cal hence Mini 30.
http://www.brownells.com/GunTech/Ruger-Mini-30-bore-specs/detail.htm?lid=15904
Type: Posts; User: zimmer
Very first one were 30cal hence Mini 30.
http://www.brownells.com/GunTech/Ruger-Mini-30-bore-specs/detail.htm?lid=15904