Picking a patch and ball size based off of slugging the barrel

[Onemancoyote]

A friend has me working on an under hammer pistol of his. He has never shot it. After slugging the barrel the grooves measure .460" and the lands measure .445". How would I go about picking a ball diameter and patch thickness to start testing with?

 

[Eric Krewson]

I don't know for sure but I would start with a .440 ball and a patch around .015 or .018 or even .020.

 

[wiscoaster]

(ball + (patch * 2) <= grooves) && (ball < lands) := first patch size.

 

[Onemancoyote]

(ball + (patch * 2) <= grooves) && (ball < lands) := first patch size.

So... (.440 + (.008 x 2) = .456.

a .440 ball and a .008 patch?

Is it (ball + (patch * 2) </= grooves)? Meaning it should be less than or equal to groove?

 

[Banjoman]

Just to start, a .440 ball and 100% cotton patch made from old sheet or pillow case or tee shirt. Lube of your choice.