I use N550 with my 6.5 creedmoor. I'm using lapua brass and berger 135gr classic hunter bullets. The groups are .5 moa or less with low SD's at 41.4 grains. My barrel is 26" long, and I'm getting 2890 fps muzzle velocity. I can push them harder with no pressure signs, but this was a nice accuracy load with very little stress on my brass.