I haven't had a 6mm Rem. for a while now, but have owned at least three, and fooled with a couple others.
As several others have already noted, Reloder 19 works well in the 6mm. If that doesn't work with a particular bullet, IMR4350 and H4350 would sure be worth a try--and IMR4451 might work even better! I've had VERY good luck with it in several 4350-type applications.
