does anyone know what size the thread is for a green mountain 15/16 fast twist breech plug ?I am wanting to change from percussion to flint ignition ,the 2 choises I have is 11/16x20 thread or 5/8x18 thread any advice would be priceless
I would call Green Mountain Barrels and ask them. Maybe Track of the Wolf would know. I know they have replacement breech plugs and I think there is a slight difference in length for the flint and cap plugs. Something to consider perhaps to get the vent and pan to line up. I don't know if the lock mortices are the same for flint and cap locks either.
I am going to guess but I bet it's 5/8 x 18 but it could be either. Pretty sure I remember the fast twist blanks on GM website being 5/8 x 18. I would call Track and get the plug there if they knew for sure.