lock flat on round barrel

[RichG]

when filing the flat on a round barrel for the lock bolster to mate up to is it customary to file flat with the contour of barrel or paralell to bore?

[rich pierce]

On most round barrels, follow the contour. If there is extreme flare at the breech like on some early profile smoothbore round barrels - which would be hard to find today, a special order - I’d cheat a little to keep the lock tail from kicking out excessively.

[Pukka Bundook]

A good few of the old ones have the flat area filed so as to keep the lock tail in, and flared out towards the front.  You will see this particularly but not solely, on doubles.

[RichG]

I'm building a Wheeler trade gun pg. 73 For Trade and Treaty. From the pictures it's hard to tell if the lock is parallel to bore or tapered. The barrel doesn't have much taper at breech so it might not be noticeable. I know some high end guns have the tail in to keep wrist smaller, but this doesn't appear to be the case with this trade gun. I'm using a 12ga barrel witch is 1.25" at breech. Maybe I'll split the difference to keep wrist from getting to thick.