Re: Going from civilian to military brass
More than just the weight difference of the brass cases is at stake. Different brass may have a different composition, and therefore a different bullet pull (neck tension) and different pressure behavior.
It would be prudent to work up from scratch in the L-C brass, but the seating depth could remain the same, I would think.
The OCW for the R-P brass is only valid for that brass/bullet/powder combination.
The reason we reload is to fine-tune all of the various components to optimum performance of the system. Change one component - bullet, powder type, brass make, etc. and the balance previously achieved goes out the window.
Paul