RUGER 77 MK2 in 7.62x39 CHAMBER SIZE

[aka108]

Have read that the AK's, the SKS's and Saigas all had very large chambers to aid in reliable chambering of the round when the piece was filthy. I owned a Ruger 77 MK2 in 7.62x39 and always used handloads that were neck sized only in the reloading process. These reloads always chambered with no difficulty in the bolt action Ruger. I really became tired of the 77 as it was less accurate than the Russian designed rifles so I sold it. Had about 500 reloaded rounds for the 77 left after the sale and felt they all would slide easily into the chambers of the Russians. Really thought the Ruger would have been close tolerenced next to what have been called sloppy chambered AK's and SK's. I couldn't begin to get the rounds for the 77 to chamber in a Arsenal AK, a Norinco SKS or a couple of Saigas. So the Ruger 77 was really sloppy big chambered and Ruger made the barrels of these in 308 as opposed to the 310 bore size of the Russian cartridge. No wonder the accuracy of the 77 in 7.62X39 was lousy. I think Ruger made the mistake of rushing this caliber rifle to market and simply cobbled it together in a hurry and dumped any good testing and neglected quality control.

 

[conhntr]

Why don't you tell us how you really feel?

 

[R.W.Dale]

this isn't a firearm issue this is a handloading issue.

A SAAMI spec chamber is a SAAMI spec chamber PERIOD.

So if you only neck sized these rounds you souldnt be suprised in the slightest they won't chamber in another gun. Dollars to doghnuts the rounds in question WILL NOT drop into a case gauge and therefore cannot be used in a firearm for which they weren't fireformed.

 

[CoRoMo]

krochus said what I was thinking. I'll never assume that my handloads that only get a neck sizing will fit into any other chamber than the one that last fired them.

 

[Grey Morel]

I'm pretty new to hand loading... so maybe this is a dumb question:

If you know that the bore size is .308, and you hand load most of your ammo, then why wouldn't you just use .308 bullets in your loads? Not only is this practice common with domestic hunting ammo, it would give you about a BILLION more bullet options.

Forgive me if I'm wrong, but it sure sounds like your either loading .310 bullets in your loads, or your shooting steel cased Russian ammo out of the Ruger, and basing your accuracy comparisons on that. Both of those are terrible ideas.

Again, forgive me If I have misread your post.

 

[M1key]

....

 

[R.W.Dale]

Another point of clarification here is the x39 ruger 77 DID NOT use a .308" bore!

It was .310 just like every other x39 aside from the first run mini30's

 

[BruceB]

krochus is correct.

I recently sold my M77 in 7.62x39 back to the gent I bought it from. It was getting tiresome, listening to his whining and begging.

As an avid cast-bullet shooter, bore dimensions are of critical interest to me. My Ruger slugged at .3105 inches groove diameter, and the majority of my cast-bullet loads used bullets sized at .311". Results were pretty decent for such a flyweight rifle; I still miss it a bit.

 

[aka108]

Neck sized only reloads may or may not chamber in another firearm. I sold off a 1909 Argentine Mauser and had neck sized ammo for it left over in the shop. That ammo will easily chamber in my 1909 Peruvian as well some 223 loaded for a Savage that was sold will chamber in the Howa but vice versa would not work. As I said, the Ruger 77 chamber was large compared to the AK, SKS and Saiga all three of which have large chambers to maintain reliabllity when dirtied up. So far as the 308 bore, some of the 77 were in 308 and later in 310.

 

[R.W.Dale]

e AK, SKS and Saiga all three of which have large chambers to maintain reliabllity when dirtied up.

This is a myth

If the chamber was appreciably oversized particularly headspace than these rifles would be unreliable and would misfire. Rimless rifle cases can be oversized in diameter to an extent. However they CAN NOT be oversized in relation to length to any great degree. Particularly a cartridge without a well pronounced shoulder like 7/62x39

So far as the 308 bore, some of the 77 were in 308 and later in 310.

this would be correct if we were discussing the MINI 30

Did you slug your bore or contact ruger???

Because folks who've done both get the confirmation from Ruger that the 77 used a .310 bore. The only folks who think it's a .308" are folks who heard from someone who heard from someone else who works behind a counter.

not my email

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 department. 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
Mark is offline

Lastly what bullets and loads did you base your ruger's lack of accuracy on?

 

[aka108]

Never did slug the bore. Didn't really see any value in doing that since it was not too accurate with the handloads nor with factory new ammo and I had decided to sell it off.

 

[R.W.Dale]

What handloads?


I will say that factory brass 7.62x39 ammo is virtually worthless in the accuracy dpt

 

[Grey Morel]

Never did slug the bore. Didn't really see any value in doing that

Again, novice reloader here... But doing so would have told you if your barrel was in spec or not. Thats important.

I find myself agreeing with Krochus yet again: let us see what recipe you were using. It would also be nice to know what brand of factory ammo you were basing your observations on.

 

[aka108]

New ammo that went down the bbl consisted of Winchester, Remington Peters, Cheetah (brass cased cu jacketed Zimbabwe), Wolf and Barnaul. Reloads were Winchester brass and primer, Accurate 1680 powder at various amount from 22 to 26 grains and 4895 don't remember the amounts but from the bottom of the recommended grains to the top. Bullets were Winchester, some soft point, some hollow point and fmj. Also tried a few bullets from Golden West, some place in Calif. The 77 would not group well with any. Tried several different scopes and nothing changed.