Nice write up. I have an lmt as well and worked up a nice load. My gun seems to prefer XBR over Varget. The XBR reduced the group size by 50%. I found my best shoulder bump to be .003 back from a 10 average of once fired in my chamber. I am using LC brass, CCI BR primes, XBR or WC846(pulled military) and either 168amax or 175smk projectiles.
I do not spend all the time with brass prep like you but I do not shoot 700yds. My range goes to 200yds. I would not mind trying 600 to see what my groups are. I am getting about 5/8ths at 100yds with 175smk's.
The gun is a blast to shoot and dead on accurate. Its repeatble accurate too. Not just one group out of 10 but 10 out of 10.
Thanks for the nice write up.........
All pulled components and no work done to brass, just bang it out on dillon 650 and shoot it. Pulled projectiles even had marks in them.