Counterbored Mosin Nagant accuracy question

[airedaleman]

What kind of accuracy (if any) can one expect from a counterbored Mosin?

 

[Deus Machina]

Mosins run a wide range. 2" to 4" at 100 yards is considered 'normal good' for one in good shape, and counterboring may or may not make an actual difference on that.

 

[caribou]

The counter-boreing was done at refurb after the war to bring the rifle into spec, and accuracy standards. It was done to bring the crown to a sweet spot and resore/repair the weapon.

Id rather have a Mosin with a counterbore than one that needs it and dosent have it.

Most every Mosin I shot with milsurp ammo was accurate enough to hunt and fight with, depending on your use.
the three most important aspects of accurate shooting is a decent rifle , a decent load and a person with decent shooting skills. A Mosin will get you there. Some need slight tweeking, some are awsome right outta the cosmoline.

 

[Onmilo]

Like all machining, counterboring is dependent on the skill or lack thereof of the machinist performing the work to produce acceptable accuracy standards.
If it was done on a drill press on saturday afternoon by a drunken guy who didn't want to be in the repair shop it isn't going to improve anything.

Russian rebuillds have always displayed a very wide spectrum of skill levels in the work

 

[airedaleman]

Thanks to all for the replies; pretty much what I figured.
Question became academic this morning, however. The local shop had advertised 91/30's for 149.95 "while supplies last." Went in and found they're down to two, and those are now 199.95! I dinna think so...

 

[C-grunt]

Ive owned a few Mosins over the years and I think all were counterbored. I never shot any for groupings but they always hit what I was shooting at. If I had to guess Id say they were 3-4 MOA rifles.

 

[carbine85]

My experience with counter bores is that they are not as accurate as one with good rifling, a good crown and no counter bore. Counter boring wasn't just for repairing damage as many believe, it was also for erosion of the muzzle. If you have that much erosion I'm betting you have some pretty worn rifling and throat erosion. I stay clear of the counter bores these days.

 

[Jackal]

A counter bored Mosin will shoot better than one with a worn muzzle. Basically restores performance to nearly "new(ish)". When I see a counter bored rifle, I know its been (likely) shot and cleaned a lot. Fella's didnt always use proper, careful cleaning methods. I suspect I wouldnt have either, being in a frozen war torn environment.

 

[Cosmoline]

There are counter bores and counter bores. In some cases it was done simply to freshen up an old crown, and can work very well. But in most cases, esp. with USSR Mosins, they not only counterbored but cut fresh rifling. This makes for a shiny bore but also expands the bore. I think that's why many of them seem to shoot less well than a truly mint Mosin. Slugging the bore with yours will tell for sure.