I've started experimenting with superformance powder in 260 rem. Winchester 243 brass necked up, CCI BR-2 primer, 140 Nosler custom competition. I started at 44 grains working up to 48 grains, shot over the crony, and closely watching for pressure signs. Amazingly easy on pressure, but but big increase in velocity and recoil. I then loaded 20 rounds with 48 grains and shot from the 600 yrd. line. Grouping was ok, but i didn't like the recoil. I saved 4 rounds then shot them through the crony. 3065 fps with a 30 in. barrel. Im loading back to 46 grains now, then trying them at a 600 match tommorrow.