Bad crown?

[Preda8or]

What are the signs of a bad crown?

[col48]

the only experience i have had with a bad crown,was when my m8 accuracy went right off,and he actually thought his barrel was shot out.
but after a good re crown job his rifle went straight back to shooting good small groups again.
this was on a custom rifle.
so the crown is a very important part of the gun and should not be over looked.
hope this helps.
Colin

[James Jones]

alot of times you will be ably to see the carbon on the crown of a gun , one sign of the crown being boggered is the carbon print will not be uniform around the muzzle.
another way to give a bad crown away is the sudden loss of accuracy. like one outing it'll shoot consistant 1/2" then the very next outing it shoots 2".
most of the time you can use a brass lap and just lightly lap the muzzel and that will fix it but sometimes it'll need to be recut. I have ALL of my factory guns crowns recut from the git-go its a good investment to haveba better crown cut with a recess to help protect it.

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<font color="purple"> I have ALL of my factory guns crowns recut from the git-go its a good investment to haveba better crown cut with a recess to help protect it. </font>

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Good post!

I sent Kirby my factory 270 WSM for a muzzle break and trigger job. It shot better after it came back. I assumed it was because of the trigger job. Is the crown changed when a muzzle break is added? Seems to me a muzzle break is good insurance to protect the crown.

[Fiftydriver]

My method of fitting a brake is to chuck the chamber end of a barrel in the lathe chuck and support the muzzle at the other end of the lathe by the tailstock with a live center in the muzzle.

Very accurate to get the threads perfectly concentric to the axis of the bore. BUT, it also basically ruins your crown by doing this.

No worries though, every rifle I brake gets about 50 thou cut off the muzzle end and recrowned anyway when the brake is fitted, just part of the brake job and a requirement because of how I support the barrel for machining.

I would suspect most of your accuracy increase came from three areas, better trigger, Much better crown and the fact you did not have to worry about recoil [img]/ubbthreads/images/graemlins/grin.gif[/img]!!

I would agree, recrowning a factory rifle is very cheap and often provides good returns on your money!! The sad thing is that to cut a match grade crown, it takes about 15 minutes at the most and the proper tooling and piloted cutters. Its a shame the big rifle makers can not take 15 minutes to get it right.

Kirby Allen(50)