Ruger Data on 7.62x39 Rifles
I posted this reply from Davidson's Gallery of Guns website a few months back on this very same topic. It is a reply to my request of the bore size on the Ruger M77 in 7.62x39. As she states, the info came directly from Ruger. Davidson's is located in Prescott, Arizona, same location as the factory that builds Ruger rifles:
Dear Mr. Phelps,
Thank you for your inquiry at
www.GalleryofGuns.com!
Ruger's groove diameter for the 7.62X39 caliber cartridge for either the Mini-30 or model 77's is .3100 - .3115 according to their engineering dedpartment. This is a compromise diameter designed to shoot either the .308 or .313 diameter ammo
that is available.
A .311 diameter bullet would be my choice for handloading applications if available.
I hope this helps!
Sincerely,
Rebecca L. Gridley
Web Administrator
Davidson's/GalleryofGuns.com