It strikes me we're talking two different games here.
The 6.5-284 is a great target round, and it is also a barrel burner. 1000-1300 rounds seems to be about it for competitive barrel life. But competitive shooting is a different game than wanging away at 450 yard clay pigeons. In a heavy barreled target rifle, it may be worth it. Whether it is any better than a 6.5X55 or 260 or a straight 284 is open to debate.
It of course can also be an accurate round in a lightweight sporter, as the groups above can show. But it's impossible to prove, empirically, that there's any superiority. I've got a MR contoured 280AI that can match those groups above, virtually on demand. I've got a 52 year old M70 270 that will hang in there as well. It's a neat cartridge, but to take a 3-shot 100 yard group in a lightweight sporter (in any cartridge) and conclude anything meaningful about the cartridges abilities is wishful thinking. You can't compare these groups with the 10 or 20 shot group out of a target rifle. That lightweight rifle could be a 250 Savage or a 270 or a 308 and the targets would be similar.
It does keep the mental gymnastics at work though, justifying why ours is better than the next guys, huh?
