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What `s counterbore for on rifes?
Sam I Am
Member Posts: 5 ✭✭
What`s counterbore for on rifes? Thank`s Sam I Am.
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The way to fix that is to recrown the barrel by cutting off the end with the damaged rifling, and polishing it up, but that's a bit difficult to do, and it can't be done on guns where the sight sits right above the end of the barrel.
So the "poor man's" version to fix up the bad rifling at the end of the barrel is just to drill away the bad rifling, from the inside, leaving the gun with a slightly widened bore at its end.
This is called a "counterbore", and its particularly common on older Mosin rifles, with many of them being counterbored as a matter of routine when refinished for arsenal storage.
Counterbored Mosin barrel (left) and normal barrel for comparison (right):
Edit:
Here's another "cartoon" of same:
http://7.62x54r.net/MosinID/DCounterbore.jpg
Richard Franklin comes to mind as one who does that.....
The edges of the rifling on the inside, still needs to be concentric to the bore or accuracy will suffer... not a job for a drill bit.............