Counterbored?

[Geodetic]

I see this term used with many surplus rifles. Especially "counterbored at the muzzle". What does this mean and how does it affect accuracy, shootability etc? Thanks

[Bhobbs]

In some cases the crown of the barrel is messed up beyond repair or the last few inches of the rifling is gone so they drill out the barrel to a larger diameter to clean up the bore and reach better rifling. This can actually improve the accuracy of the rifle.

[mauser98k]

counterboring is when a rifle's muzzle (usually just the muzzle) is so worn out or damaged that it will affect accuracy.

the arsenal drill down the muzzle to remove the damaged section. a counterbored rifle will shoot better than a rifle that has a damaged or worn out muzzle.





counterbored on the left. normal on the right

[mdouglas1980]

My M38 is counter bored and is super accurate.
The really easy way to tell if your rifle is counter bored is put a round in backwards down the barrel and the bullet fits snugly in the end of the barrel; then you know it's not counter bored.