I am having some problems loading a 303 with Metford rifling, kind of an oval bore of sorts. A seated cast lead .3135 bullet has to jump 3.50" to hit the rifling. I may try BP to "bump" up the
base to a larger diameter and therefor hit the rifling earlier.
Right now my cast bullet loads "key hole", but jacketed .312 Woodies don't, but has to jump to 3.8"
to hit the rifling.