If I were to shoot a 6mm (haven't, don't, likely won't), it would be the .243 Win.
I do shoot the .260 Rem, and do it because of the commonalities inherent in the .308 source cartridge. I set my headspace for the 260 and 308 using the same H/S gauge, and use the same case length gauge. I even make my 260 brass by necking down 7-08; which reduces vulnerability to 260 brass shortages, and actually costs less per case, to boot. Much of this is quite the same for the 243.
It's enough gun, and capable of running decent velocities without requiring higher pressures and temps. Being somewhat overbore, it can convert this configuration into a longer barrel, slower powder 'loafer round' that still delivers good velocities, with all this offering a possibility for longer bore/throat life.
OK, it's not the flavor of the day. It's old (Eeewww...), and not sexy. So's the 260 (imagine that, calling the .260 old, but I've been shooting it for going on two decades).
If there's a plan to develop even more new 6mm bullet styles, I suspect there's not a lot of room left for innovation on that score. This is not exactly terrible news.
Just pointing out the obvious. Some folks probably could use the reminder...
Greg
