I have great luck with any short action. 300WSM, 270WSM, 308, 243. Velocity spreads are very low, and very dynamic load. I have yet to load for the 6.5/284, but from what I seen from my friends, they have extreme good luck. Don't expect 16fps spread with a 300RUM, or 300win mag or many of the long action calibers no matter what is printed here. Sure, I have gotten them to shoot just as good. But its so easy with the short actions, in my opinion. I get velocity spread upwards of 50 to 70fps with my 300RUM. This is with a custom gun and two others. I get them to shoot .5" groups at 100yards but you can see this velocity spread over 500yards. I start getting verticle spreading.