Dropping a deer in it's tracks is a product of bullet placement and bullet construction...Any modern centerfire rifle is capable of doing this...My niece does
it quite well with a 22-250 and 60gr Nosler partitions...I do it whenever needed with
my .243 and 100gr CoreLokts...I've done it with my brother's .270 and 130gr Sierra GameKings...
Nothing to do with the diameter of the bullet being put into the deer...
As far as those big tough deer that a .243 won't handle...How in the heck do you guys eat those things??? Parboil them???
One of my brothers takes a trip to Canada every other year, his guide uses a .243...
I've killed 6 black bears with my .243, the largest weighed over 350...Are your big deer tougher than bears???