Ruger Hawkeye bore diameter in 7.62x39

T

tahunua001

New member
hello all,
I was just curious if anyone knows the actual bore diameter of the Ruger M77s that are chambered in 7.62x39mm. the other day I was told that they actually have a .308 diameter bore instead of .311 as is customary with 7.62x39 so I was just wondering if anyone has taken a pair of calipers to their gun to verify this.
 
I believe Ruger got away from using incorrect diameters when relatively inexpensive ammo arrived. Mind you, their site indicates no M77's in 7.62 x 39.
 
it has likely been replaced, they often make only a runs of a cartridge and then replace it for something else. rest assured they do exist. my brother bought one last year.
 
I looked into one when they first came out and that was one of the things that turned me off on it. I have no idea if they ever changed it or not. I believe their mini thirty was .308 also. There may be more guns like that out there too. I had bought an RCBS Die set and it came with both expander balls included.
 
I believe Ruger got away from using incorrect diameters when relatively inexpensive ammo arrived.
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So are you saying that they moved away from .308, the incorrect diameter, and went back to .311, the correct diameter, at some point in the last 10-20 years? Just making sure I understand you.
 
I believe their mini thirty was .308 also.
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Yes. No. And, "only at one end of the barrel..." (Seriously.)

...But that's a totally different subject.


(...) the other day I was told that they actually have a .308 diameter bore instead of .311 as is customary with 7.62x39 (...)
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Standard groove diameter for 7.62x39mm barrels is 0.3105".

I dug up an old thread on another forum, with a quote from Ruger customer service, in regards to the barrel specifications on the Hawkeye Compact in 7.62x39mm, dated 9/24/2009.
The important information from within it:
Bore diameter production tolerance was 0.3000-0.3015".
Groove diameter was 0.3100-0.3115".

So, no, they did not have 0.308" groove diameters.


...But with that bore diameter, you can probably get away with shooting 0.308" bullets without much performance loss.
 
I used to have a Ruger 77 in 7.62x39 and I slugged the bore at .311

I also had a later Mini 30 that I also slugged at .311

It's my understanding the very first Mini-30's used .308 bores, but then switched to .311
 
It's my understanding the very first Mini-30's used .308 bores, but then switched to .311
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Yep, pretty much.
Ruger did use an unconventional approach to the matter, though. Some people say the barrels had long throats. Some people say they had tapered bores. No on ever agrees. But, the bottom line is that the muzzle had 0.308" groove diameter, while the chamber end of the barrel had a 0.312" groove diameter and a long throat.
In '92 they transitioned to the ".311" barrels and a standard throat.
 
That makes a lot of sense. If the neck and free bore are reamed to .311, you could shoot .311 bullets down a .308 bore and never know the difference. Accuracy will tell you nothing at deer hunting ranges. I had quite a few .311 barrels that shot great with .308 bullets. The only one I have left I LOAD with .308 bullets because it shoots better. I would go with Ruger having used .308 barrels on their early bolt actions. The thought of "Choked" rifle barrel does not sound right to me.
 
Did anyone ask Ruger???
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Technical questions directed at Ruger, especially for models that had significant changes made over the years, will only get you information on the very last variant that was made. And, often, the answer is directly out of the owner's manual. ....If you get an answer at all.


In my first post in this thread, I provided Ruger's response from when these rifles were still in production (meaning it's the correct information). They have ".311" barrels.
 
OK, I had to go look to make sure my memory was serving me correctly. My 4th printing (1994) Hornady load book states that Ruger uses .308 barrels on their mini-30. I kinda trust that over a sales brochure. I have RCBS dies and there is both a .308 and .311 expander ball included. This is just a cracker barrel argument anyway. I cannot say for sure, but would bet the neck and freebore on the chamber ARE for a .311 bullet. Nothing will happen if you shoot .311 bullets. Nothing ever has happened or there would have been a law suit by now. Fire away.

If you are interested enough, P.O. Ackley did some testing with an 8mm and .30 caliber that parallels this discussion.
 
I became tired chasing an M77 in 7.62x39 that shot well, rifle after rifle both stock and after tweeking just wouldn't shoot well. I finally bought my first CZ527 and couldn't be happier, stellar accuracy right out of the box.

I really wish Ruger would offer the American Ranch in 7.62x39 and in stainless, they would sell a heck of a lot more of those than the ones they offer in 300blk.
 
I always thought that out of all the big name manufacturers, Ruger had one of the best made bolt actions. I also thought their barrels were not as well made as other companies.
 
Ruger

I have two Rugers in the x39 caliber, an early Mini-30 bought in the Clinton era, and a stainless lightweight boat paddle M77MkII, the bolt rifle purchase about 5 years after the Mini. I have not slugged either.

That said, the Mini has shot all manner of x39mm ammo. Both rifles have seen .308 dia reloads, the Mini has seen ammo from across the board and has been shot quite a bit. The M77 seems to indicate a bit higher pressure using .310 slugs during a recent search for a new x39mm slug, but that could be due to any number of factors. The vast bulk of the bolt rifle shooting has been with the now discontinued Sierra 135 SSP bullet intended for the .30 Herrett.

Regards Ruger barrels, the early Ruger barrels on the M77 were contract barrels as I understand it, and sometimes barrel quality was not what it could be. When Ruger started making their own barrels (not sure when, likely when the MkII hit the market) barrel quality overall is believed to have improved.

My Mini30's accuracy is so-so, but the M77MkII will shoot into 1.5MOA with reloads assembled without any accuracy tweaking.
 
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