I have both and I find myself reaching for the 6mm more and more why? I have no good reason, I just like it. As others have stated the 6mm is better on paper but that coyote or speedgoat is not going to know any difference when hit by one or the other. Prior to 67 I believe the 6mm had a slow twist that would not stablize bullets that were greater than 80 grains that changed and now most have a 1 in 9 twist. This will allow one to shoot the 105 grained bullets to good satisfaction in most firearms chambered in this round. So if you have all the stuff go with a 6mm and be different, if not stay with a .243 and be like all the rest.
