Sponxx,
I've never seen 66grn R22 show pressure signs on any 7rm I've ever loaded for(own 3 currently and have loaded for many others). IMO you can go higher, but I would always start at 65 and 66 for the first loads based on experience. BTDT too many times with too many 7RMs. What I see in your groups is two together, one off, which is often cured with seating depth adjustment. Move to 66 and tinker with depth. Try 4 touching to .003 off, 4 at .010 off, 4 at .020 off, etc and find the sweet spot. I have never found any use for less than .5grn powder adjustment until the best whole grn number is found, best depth, then .5 to see change(then lower increments if needed). You can chase your tail to no end with this stuff, but you'll find over time a system that works.
Good Luck
loder
