Counterbore

[almiz111 26]

I have the itch to buy a Mosin and am mostly unqualified to judge quality.

 

One special unknown is 'counterbore'. Can you help with how/why/when/where?????? Is it basically a rebore of 1/4 in. of the muzzle end? Is it only done to well worn barells?? I am guessing it is to be avoided at all cost.

 

Thanks,

Al

[Malsua 1,422]

I have the itch to buy a Mosin and am mostly unqualified to judge quality.

 

One special unknown is 'counterbore'. Can you help with how/why/when/where?????? Is it basically a rebore of 1/4 in. of the muzzle end? Is it only done to well worn barells?? I am guessing it is to be avoided at all cost.

 

Thanks,

Al

 

Nothing wrong with a counter-bored Mosin. I'd rather have a counter-bore than a Mosin with a crown that's worn smooth from abuse or the cleaning rod. All it is doing is cutting out the bad riflings. The round may lose 1 fps in velocity or some other insignificant amount. I wouldn't sweat it if the rest of the gun is in good shape as a counter-bored version may out-shoot a regular crown.

[GRIZ 3,369]

Its done to repair a muzzle crown that has been damgaed usually by sloppy cleaning (letting a steel cleaning rod bang against the muzzle) or if the firearm has been dropped on the muzzle. A nice clean crown is important to accuracy as that's the last part of the barrel to influence the bullet. It's usualy a counterbore deep enough to remove the damage and restore the crown. I've never seen one 1/4" and if it were a 1/4' I would suspect its been recrowned several times.

 

Not something to be avoided AFAIC. It shows the muzzle has been trued up. Common in many milsurps. Its the only way the muzzle can be fixed short of a rebarrel. Many inaccurate rifles have been turned into accurate rifles with a recrown.

[Maksim 1,504]

most Finn capture rifles were counter bored by the Finnish to improve accuracy. As a collectors item, it would make a tad of a difference in price, but for a shooter, nothing wrong with them.

 

Most carbines such as m44 and m38 were counter bored. A lot of the 91/30 were too.

[usnmars 136]

I personally avoid a counter bore at all costs. Just my thing. There are enough mosins out there that you can almost always find one with a mint bore. If it is a hard to find milsurp such as a fn49 or a Hakim I will go with it but if it is a common milsurp a counter bore is an automatic deal breaker for me. Like I said, it is just my thing.