Good post Lloyd!!
The 44/45 IS .429-.454 AT impact. A 243 may be faster and WILL expand. But thinking it would ever attain the diameter of the pistol rounds ARE is foolishness. Not to steal the 243's thunder either. It's a great round. But for my money, inside say 125 yards, I'll take the properly loaded pistol round ten times outta nine! Load the pistol rounds with a hard cast bullet with wide mepat like a LBT or a WFNGC that can and will penetrate thru and thru and look out!! Foot pounds,"shmoot pounds"! Physics dictates, your not hitting that animal with any more force than you feel against yor shoulder firing the round! I'll take the 100% gaurented, 45 caliber hole. Coupled with, thru and thru penetration, to most anything else with in say 125 yards.
The bullet diameter at impact is something many of the Killing or power "formulas" miss. I still look to the foot pounds as kinda a " litmus" scale for game. IIRC the Taylor TKO scale does take bullet diameter into account.
CW