>>Richard tells me 1000 gr ULD RBBTs are a possibility!!!
Hey Kirby, I probably missed it, but what twist? I have a new fast twist (9.5) SA 50 BMG
I had built specifically for 800gr and higher pills, sub-sonics and .308 Sabot's. (no muzzle break when firing sabots).
It only has a 30" pipe and not nearly as hot as your 510 AM, but it should be good for load dev and experiment.
As soon as I get Richards site
updated I'll email him and order some big 50 BMG pills.