Ruger 77 in 7.62x39 ?

14 February 2008, 10:05

Is the Ruger 77 MKII chambered in 7.62x39 a .308 groove or is it .311? I get a bit confused when talking about groove and bore diameter, but I think it's the groove diameter that determines the bullet diameter. I think I remember the Ruger is for .308 bullets.

Thanks for info.
KB

14 February 2008, 15:41

Sambar 9.3

If it's the same as the ones shipped to OZ, then it's a 308...

14 February 2008, 19:07

Krochus

The short answer is IT DEPENDS you need to slug your bore

http://thehighroad.org/showthread.php?t=178431

read post number 16 as it pertains to your rifle

posted on 10-16-06 by BruceB

quote:
I'm a long-time, devoted, cast-bullet nut of the worst sort, and internal barrel dimensions can be critical in the cast-bullet game.

Therefore, when I obtained my stainless Ruger Model 77 bolt-action in 7.62x39, one of the priorities was to find out what the bore dimensions REALLY are. As mentioned earlier, the lead slug doesn't lie.

Are you ready? This 7.62x39 M77 Ruger bore has a groove diameter of .3105", definitely NOT a standard .308" barrel. It was slugged three times to be absolutely sure of the result.

It has now digested well over 150 separate and distinct cast-bullet recipes, ten rounds per combination,with bullets from 130 to 220 grains, all sized at .312". Powders ranged from Unique to IMR 4350, and decent results were obtained with quite a few of my loads.

----------------------------------------

If you waste your time a talkin' to the people who don't listen
To the things that you are sayin' who do you thinks gonna hear
And if you should die explainin' how the thing they complain about
Or the things they could be changing who do you thinks gonna care

Waylon Jennings

15 February 2008, 02:56

Con

I have an original test report from an Australian magazine ... I'll check it out, but remember twist was given as a fast 1:10".
Cheers...
Con

15 February 2008, 07:57

Leftoverdj

The early Ruger Mini-30s had .308 bores. That did not last long, but the rumors have.

17 February 2008, 01:15

Con

Not much help, but the test report on the 7.62x39 cartridge using a Ruger MkII stainless/synthetic stated that fired cases from the Ruger MkII would not accept a 0.310" projectile but would allow a 0.308" projectile to slip into the case. There is also reference to the Ruger's "tight-bore" suggesting its 0.308".

Hazy memory tells me that Clymer produced and had available a hybrid reamer than allowed 0.311" projectiles to be used in 0.308" bores and that Ruger may have used that chambering? Tested with ex-mil ammunition the Ruger MKII did fine, less successful where the Mini-14's where extractor damage was noted with some brands of ex-mil. The term "rubber micrometer" is used to describe manufactured 7.62x39 ammunition and its variations.
Cheers...
Con

17 February 2008, 02:52

Sambar 9.3

quote:
Originally posted by Leftoverdj:
The early Ruger Mini-30s had .308 bores. That did not last long, but the rumors have.

That must have been the variant I had...
Made (IIRC) around '96?