TimH
Member
I think it has to do with the muzzle and making the opening "true" again. Is this right? How do they do it? Thanks Tim
What is Recrowning?
- Thread starter TimH
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Barrel is placed in a lathe and then the muzzle retouched.
There are different types of crown. You can have a flat muzzle or even a stepped muzzle (think of the reverse impression of a dime resting atop of a penny) which offers the advantage of slightly more protection for the actual muzzle. There are "coned" muzzles where the muzzle is tapered towards the lands or grooves to facilitate loading (muzzle loading black powder guns). There's also a 10 degree dished out muzzle (slight bevel downwards towards lands & grooves).
There are different types of crown. You can have a flat muzzle or even a stepped muzzle (think of the reverse impression of a dime resting atop of a penny) which offers the advantage of slightly more protection for the actual muzzle. There are "coned" muzzles where the muzzle is tapered towards the lands or grooves to facilitate loading (muzzle loading black powder guns). There's also a 10 degree dished out muzzle (slight bevel downwards towards lands & grooves).
cracked butt
Member
Pretty much.
The idea is to make the muzzle square with the bore and have fresh undamaged rifling at the end of the bore.
There are cutting tools that have a pilot that fits in the bore and cutting head that recuts the crown that can be used in a lathe or with a T-handle to recut crowns.
Some do-it-yourselfers, including me have had success with using a large brass carriage bolt or screw with the round head covered in valve lapping compound chucked up in a drill press- I'd only do thiswith a cheap old rifle that isn't worth the price to have a smith redo the crown.
P95Carry
Moderator Emeritus
Just to add ... it seems generally recognized that perfect truth (in the perpendicular ....... or ''normal'' to bore axis) ...... is critical, the last 1" of the barrel affecting accuracy more than any other single feature.
If you consider a damaged crown ... then just at the instant the bullet leaves barrel .. there can be a gas-pressure ''push'' slightly off axis .... as gas escapes preferentially in one direction to the side ....... this at 100 yds and plus, will be potentially well over MOA category.
If you consider a damaged crown ... then just at the instant the bullet leaves barrel .. there can be a gas-pressure ''push'' slightly off axis .... as gas escapes preferentially in one direction to the side ....... this at 100 yds and plus, will be potentially well over MOA category.
shermacman
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P95Carry nails it.
The burning gases that shove the bullet down the barrel explode turbulently at the end. That blast can push the bullet just a touch if the crown isn't perfectly even. Even a slightly uneven breath of that hot gas will throw the bullet way off after 100 yards. Bleeding off the gas evenly can also be done with ports and compensators.
The burning gases that shove the bullet down the barrel explode turbulently at the end. That blast can push the bullet just a touch if the crown isn't perfectly even. Even a slightly uneven breath of that hot gas will throw the bullet way off after 100 yards. Bleeding off the gas evenly can also be done with ports and compensators.
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