I've been working on a cast boolit load for my 300 BO. Typically I size all my cast boolits for 308 groove diameter barrels .311" and it's always worked great.
It seems with this cartridge the shoulder to neck relationship is causing my .311" boolits to effectively move the shoulder forward just enough to make them stick in the chamber.
If I seat a .308" jacketed bullet there is no issues.
Has anyone else experienced something like this with the 300 BO?
Motor
PS: A .309" size die is in route. 👍🏻