I have the 244 and 6mm just different twists.
If I am killing animals for meat I go out of my way to skull or neck them as to not waste meat and have found that the 6mm doesn't take the whole head off like the 25 06 or the 264 wm does on ocassion.
What ruined the popularity of the 244 was the wrong twist to start with and winchester came out with one that would stabilize 100 grain or better bullets. In an attempt to save a great round Remington changed the name to the 6mm, but it was too late as the older gang still believing that all bullets in that round blew up on blades of grass. The 243 won out and the 6mm died off.
The 264 winchester had a hell of a following back then and as a payback remington put out the 7mm mag which that along with some creative back stabbing and mudslinging really dented the 264's popularity. Load both with the same grain bullet and see which one works better.
Everyone's good friend
@Bob Nelson 35Whelen is pretty sure of what he likes and with that I believe he's pretty hot with the iron though I can't really figure out his dislike of the 243 as an loaded with as same weight bullet as speed an as as an kina as same.
It's all good....