303 hunter
Member
I was reading a thread in the for sale section. Someone asked if an M38 Mosin for sale had been counter-bored. What was the purpose of counter-boring?
Mosin M38 Counter Bored?
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Shadow 7D
Member
remove damaged rifling and INCREASE accuracy
Rifle 'surgery'...
Counter-boring is a cheaper way to salvage a damaged muzzle, but it will only partially restore the rifles accuracy. It's better than throwing away the entire rifle, but accuracy will never be better than minimally adequate. Avoid a counter-bored rifle if possible.
Counter-boring is a cheaper way to salvage a damaged muzzle, but it will only partially restore the rifles accuracy. It's better than throwing away the entire rifle, but accuracy will never be better than minimally adequate. Avoid a counter-bored rifle if possible.
Shadow 7D
Member
NO, it will never be as good as a pristine barrel
so go find one of those, as most damage occurs at the muzzle, removing the damaged part, counter boring, improves accuracy, so yes, it will shoot worse than a pristine barrel, but once again, try finding one of those on a 100+ year old rifle.
so go find one of those, as most damage occurs at the muzzle, removing the damaged part, counter boring, improves accuracy, so yes, it will shoot worse than a pristine barrel, but once again, try finding one of those on a 100+ year old rifle.
TurtlePhish
Member
It's actually entirely possible it could shoot the same as an unbored barrel... (Very) Unlikely, but possible. Depends on the quality of the crown put on the end of the barrel inside the counterboring and the concentricity of the counterbored section of the barrel. It's harder to get these right than it is to crown an unbored barrel, so it happens right less often.
elwoodm
Member
that and the counterboring takes almost an inch of lands and grooves out of the bore. a new crown would only be an 1/8 or 1/4 of an inch but the refurbishing people will not go that far. takes a special tool to crown. dont complain i wish i had a m38 bored or not.
Maverick223
Member
While not a desirable trait, a counterbored barrel is nothing to fear if performed right. IME they usually aren't that bad.
TurtlePhish
Member
Won't hurt accuracy. Just lowers velocity a little bit.
Shadow 7D
Member
They don't remove the crown, rather the remove the length of rifling that's thrashed by untrained peasants shoving a steel cleaning rod down the barrel....
Lovesbeer99
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I had a VZ24 that had a counter bored barrel and it shot just fine with my hand loads. Just understand what you are getting and what it will be used for. I bought mine to play around with at the range, not as a tack driver. Then I planned to use it as a base for a custom but eventually just sold it.
Also note that it will lower the value compared to a non bored gun (but only if the non bored gun has a decent bore and crown) so don't over pay for it.
Also note that it will lower the value compared to a non bored gun (but only if the non bored gun has a decent bore and crown) so don't over pay for it.
Tempest 455
Member
My M38 shoots just fine w/ a counterbore.
My seeing it. What I can remember is there is a barrel crown called an "accuracy crown" where the muzzle is cut off square and then a concideral recess is milled in the face of the muzzle. In this set of photo's it would be the one with a white stick in the bore.
http://search.aol.com/aol/image?q=rifle+muzzle+accuracy+crown&v_t=comsearch51-txtlnkusaolp00000051
I dont see much difference between the accuracy crown and arsenal couterboring with the exception of how big the counterbore is.
I've also noticed that some US military issure sniper rifles have a counterbore or accuracy crown. Seems like a good thing.
'loose
http://search.aol.com/aol/image?q=rifle+muzzle+accuracy+crown&v_t=comsearch51-txtlnkusaolp00000051
I dont see much difference between the accuracy crown and arsenal couterboring with the exception of how big the counterbore is.
I've also noticed that some US military issure sniper rifles have a counterbore or accuracy crown. Seems like a good thing.
'loose
Maverick223
Member
Loosenock, I think the crown that you are referring to is a recessed target crown (often specified at 11 degrees in the stepped portion). The main advantage of such a crown is to prevent damage to the most sensitive and critical part of the barrel. It does not influence the accuracy, in fact most benchrest shooters prefer a 11 degree crown all the way to the edge of the bbl (it is an easier crown, and therefore a bit more precise on average). A counterbore will perform like the recessed crown, but this wasn't a contributing factor in the decision to perform the operation (they just wanted to remove the damaged portion of the bbl).
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jason41987
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my M38 has a very, very nice bore to it, looked like it hadnt even been fired, but it was also counterbored.. apparently it was a practice they regularly did for a long term endurance and reliability reason as well, if someone damaged, dinged, or scratched the end of the barrel, it wouldnt do anything for accuracy... so i think they though ahead about some idiot putting their rifles muzzle down in the dirt
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