It's not necessarily the length as it is the diameter of the nose and ogive shape,...
A fact that was made apparent when I was loading those 450 gr. bullets for the 50-140. These short nosed little bullets (for a 50 cal!), both the 450 gr. Barnes Originals and those cast from an RCBS 50-450 FP mould, would not let the loaded round fully seat in the chamber if the bullet was loaded even a little long.
But unlike the 450 gr. jacketed bullets, in the cast bullet's case it wasn't the ogive but the upper driving band that prevented it from fully seating.
Seat them to the crimping groove or the cannelure and they bottom out with a resounding THUNK!
Now that y'all got me thinkin on it, don't some folk say you get better accuracy with cast bullets if they are seated into the rifling...

If so, maybe I could load the bullet long and force the upper driving band into the rifling when I load the rifle.

What ya think?