Ian
My last 6.5-284 was a 26" 1-8 twist Hart Barrel (Sendero contour)set in a Sako Varmint McMillan stock. I would have kept it but the short action drove me nuts. It loved the 140 A-max. with either R-22 or H-4831. It also shot great with 120 NBT's 3250fps (the deer hated em)
I hope to also find an A-max load for the new one and test it out soon on some crop damage tags. I will post results.