The shorter, .4 nose is optimal on the 300 gr WFN in the 45 Colt because of the large powder capacity, but it doesn't change bearing length. Bearing length always stays the same regardless of where the crimp is put, but bearing surface, which is, the percentage of lead to bearing length in contact with the barrel goes down when the nose is short, which, coupled with the longer jump to rifling, means there is a slight increase in potential for the rifling engagement to strip. That last is merely a technical tidbit of information to consider broadly. The 300 gr 45 cal WFN is strong enough that stripping isn't a concern if the bullet is gas checked, or with plain base using very stout loads, which your's isn't.
