found a couple of other notes this morning on OAL in my 16" Bushey barrel. I'll double check with my bolt gun and #1 when I get a chance.
The 450 has a very generous .200 of freebore according to SAAMI specs, allows some bullets to be seated farther out like the 275gr Barnes for some added case capacity
300gr XTP mag 2.220 to the lands
250gr FTX was 2.460 to the lands (not much bullet in case)
300gr Speer deep curl 2.225 to the lands