Q1: What is the starting base diameter of your (lead) bullets before loading? How does that diameter compare to jacketed rounds?
They are .401 straight out of the box
Q2: What is the resulting diameter of your cases at the mouth of your loaded (lead) rounds?
It should nominally be 0.375-0.380", or whatever minimum drops the cartridge into the
barrel with a satisfying "plunk" when it stops.
My loaded lead rounds are .401 at the neck of the case, and the jacketed ones are .419 1/2. At that diameter they'll cycle, any larger and it's a locked up gun. However, at .401 I get the 'plunk'.