What dia would you want?

[Blammer]

I'm looking at getting a custom mould for my 20 ga slug gun. I just slugged the barrel of my gun.

It's .625 in the grooves and .620 on the lands.

If you were going to cast a bullet for this what size would you prefer?

Well I mean, What size bullet would you want sliding down the barrel at velocity?

[leftiye]

.001" to .002" over groove diameter (626" to .627"). Maybe even bigger in that large of a bore. Bigger sometimes works better. Make some one size, work uo an accuracy load, then experiment with size a little just like you experiment with hardness, alloys, lubes etc..

[Blammer]

thanks, is there a "set rule" on how big the bands should be to help engage rifling?