Quote Originally Posted by edbear2 View Post
It's a funny one, the marks on Louis' gun seem to be in the grooves not lands, I wonder if he has given it a brush. as you say a counterbore would give a slight Mercury / Airsporter effect of a larger hole for a few mm depth but I don't like sharp crowns, so would go with fine grinding paste on a ball bearing welded to a rod and some lapping, followed by a really good rinse out personally, that is how I have done a couple of damaged ones in the past with good results.

ATB, Ed
good idea on welding a BB to a rod - I use the ball/paste method myself, but was thinking it would be tricky to get the ball down in the counterbore... doh