When to touch up a crown

[Gene]

Some say retouching a crown will improve accuracy. What are the visual signs that indicate the need to do so? Is rubbing a Q tip inside the muzzle accurate?

Would it be a good idea to buy this tool and use it occasionally?

BROWNELLS 45° BRASS MUZZLE LAP | Brownells

 

[sable tireur]

Some say retouching a crown will improve accuracy. What are the visual signs that indicate the need to do so? Is rubbing a Q tip inside the muzzle accurate?

Would it be a good idea to buy this tool and use it occasionally?

BROWNELLS 45° BRASS MUZZLE LAP | Brownells

Re-cutting a crown is often done during a chamber set back procedure so that the barrel is only removed once from the action for both procedures. Cost efficiency. But if you notice an immediate drop off in accuracy, check the crown for a ding or other aberration which might contribute to a lesser performance.

There are usually two schools of thought on how much to remove. Most consider that a small cut 0.020" to 0.100" is more than enough to freshen the crown and restore some of the accuracy lost through shooting and cleaning. The other thought has been pushed by Bill Shehane, who advocated cutting an inch off the crown when the shooter sets the chamber back. He feels that his accuracy is enhanced by cutting off the 1". Note that your barrel is now shorter by 2" at least when this procedure is followed.

The lap is exactly that, a lap, which just polishes a surface and doesn't really remove any real amount of material. Laps are usually used to polish out minor machining marks.

Regards.

 

[Laelkhunter]

I would be really cautious about using that lap from Brownells, unless you know what you are doing. I don't have any knowledge in using one, so I wouldn't even try. You might make it worse.