Best way to break the inside edge of a muzzle

[Tumblernotch]

My muzzle cut on my 20 ga. is sharp on the inside. Starting patched roundball is hard because of it. Is there an easy way to chamfer the inside of the muzzle cut? I just want to break the sharp edge...

A quick way to put a shallow, uniform bevel in your muzzle is to take a slightly oversized ball (in your case a .69 cal. or 16 ga.) and wrap it in a patch. Dip this in some valve grinding compound and work it back and forth. This will put a light, highly polished crown on it. I use this after using a crowning tool to polish the crown.

 

[Vaino]

Irregardless of what treatment is given the "mouth" of the bore, if it's uniform around the dia. and allows the patched ball to be pushed in w/o tearing the patch, it won't affect accuracy. This is no "big deal"....I just don't want to impair any of the "built in" accuracy of the bbls that the manufacturer ensured would be there because it's so easy to install a uniform chamfer.....Fred

 

[Bubba45]

Best use a lathe with barrel dial indicated to ensure its running true before chamfering muzzle then .
Thumb , ball bearing , oversize ball etc. , all the same and will not be as accurate of job as can be done with lathe .
But ...........for errors in most shooter situations I highly doubt would be any noticable difference in accuracy between any of the methods .