Tinker,
Success. Two good chamber casts. 1.6 inches from the rim of the cartridge until the chamber necks down. There is then a .2 inch smooth area until the rifling starts. The wall of the chamber is .78 inches in diameter. The .2 inch smooth area after the neck down, and prior to the start of the rifling is .72 inches in diameter. It has 8 lands and grooves. Groove to groove is .715 inches. Now what do I do?

Gramps

Size Does Matter