Re-boring a Ruger 77 from 7x57 to 8x57?

[Kestrel]

I'm thinking about getting a Ruger 77 in 7x57 for a pretty good price. I've heard the Ruger 77s in 7x57 can tend to be inaccurate, due to a long throat length. If this gun turns out to be inaccurate, is there much to having the barrel re-bored and rechambered to 8x57? Approx. what would it cost? Is it cheaper than having it rebarreled?

I'm actually thinking about getting two of them and having one converted to 8x57. I've been wanting a factory rifle in that caliber... just because. (I don't think I want the new Rem 700 Classic.)

Thanks for any help,
Steve

 

[Gewehr98]

Before you throw the baby out with the bath water...

Find out if it is indeed inaccurate (that means shooting it), and if the long throat is actually the culprit. And the fix to a long chamber throat isn't reboring the barrel to a larger caliber. It's knocking a few thread lengths off the breech end of the barrel, say, the length of the too-long throat, rethreading the shank a little further up the barrel, and running the same size chambering reamer that made the first chamber into the now-shortened barrel. Voila'! Same 7x57, no more long throat.

Now, if you're really bent on getting an 8x57, that's fine. But a 7x57 is a fine rifle chambering in it's own right.

 

[Kestrel]

Gehwer,

Of course! I completely didn't think of that. That's what I'll do. Since I'm getting this gun for a good price, I think I'll get two and still have the second converted to 8x57.

Is there anything more to the conversion, other than re-boring and rechambering? By the way, who would be a good gunsmith to do the rechamber? Is it a specialty to do that to a barrel?

Thanks again,
Steve

 

[Jaywalker]

The process is called "setting back" the barrel. I'm sure most 'smiths would be "willing" to do it - choosing who you "want" to have do it is different.

Oh, BTW, the theory is that the bullet should just touch the lands, I believe, and that a "jump" to reach them is the source of inaccuracy. (This jump tends to keep pressures lower, however, I understand.) Some rifles perform well with this gap, however. Weatherby has used it consistently because of their high-pressure loads. I understand Ruger does too, but I haven't heard why. Even with this approach, Rugers can be very accurate.

Jaywalker

 

[bogie]

FWIW, you aren't gonna get that sucker rebored. Maybe rebarreled, but it'll be a serious hassle to drill the existing barrel and re-rifle it.

IMHO, keep the barrel that's on it if it shoots. If it doesn't, get another barrel made.

 

[Kestrel]

bogie,

Why do people recommend having this done? Can barrelmakers not do this?

Steve

 

[Gewehr98]

Bogie's right.

It's a lot less costly and labor-intensive to simply get another barrel blank in a given bore and twist, chamber ream it, thread it, and fit it to the gun's receiver, than to take a rifled barrel, drill it out to a larger bore, rifle it, chamber ream it, thread it, and fit it. You'll also find more gunsmiths willing to do the former than the latter.

 

[Bob C]

My M-77 in 7x57 was sometimes accurate, sometimes not. Three of four groups would be fine, and then I'd get one around 2 1/2 ".

The "cure" was Hornady 175 RN bullets seated out as far as the magazine allows, which is a bit over the recommended maximum length.

Now it's consistently accurate.

 

[Kestrel]

Thanks for the good info. Sounds like I'll look for someone to rebarrel it for me.

Thanks again,
Steve

 

[TooTech]

If you handload, you can just seat the bullet out a bit further so that there's less of a jump to engage the rifling.

Frees up a little case capacity for more powder as well.

 

[R-WEST]

Not wanting to stir up the pot too much, but, some early 7mm Ruger M77 barrels MAY have had some other problems, too. One 'smithy told me there were some that hadn't been stress relieved properly (of course, he also was selling me a new barrel, too, so I dunno). I've had two, a 7x57 and a 280; both were lucky to keep five shots on the paper. The 7x57 was rebarreled, and the 280 action is sitting here waiting for me to do something with it.

TooTech - Some of the shorter bullets, say 130 Speers, 139 Hdy Spires and 140 Sierra Pro Hunters, as examples, will just barely be seated in the case if you seat them out to within a few thousandths of the lands, with the long throat of a typical 7x57.

R-WEST

 

[Jim K]

I agree that installing a new barrel is easier and cheaper. Further, it can be done by any competent gunsmith. Reboring and re-rifling, on the other hand, is the province of barrel specialists, of whom there are few, and those very busy. Now if you intend the rifle for your great grandson...

Jim