6mm has faded while the 243 continues to shine. Sales figures for rifles and ammo are heavily tilted toward the ever popular 243. Unfair but true.
I've taken many mulies and 'lopes with my Remington rifle in 243. None got away. For several years, I favored Winchester Power Points in 100 grain. Wide wound channels are the norm but seems like the bullet ALWAYS stays within the animal. No exit hole yet results are quick and lethal.
About 9 years ago I switched to Black Hills Ammo featuring 95 grain Nosler Partition bullets. The Partitions blow out a ghastly exit wound just like 25-06. No kidding!!
In my opinion, Premium bullets have upped the
lethality index for 243 (and 6mm) to match 25-06. This is saying a lot but I've observed the results as an eye witness so to speak. Nosler's 95 grain Partition is a superb mule deer killer.
Jack