The problem with Varget in a progressive isn't the variance in charge weights, it's the occasional bridging you get that really throws the charge weight of a couple of cartridges off.
Well I'll just leave it at this.. I've loaded a couple rounds or maybe a few ten thousand more than that on a 550 with Varget and RL15 and TAC over some years. Never saw a weird shot of any of those rounds really that I couldn't blame me on,. Granted high-power matches, not BR, but IIRC I did have the bars amended and did jiggle the press, plus a powder check system accounted for anything WAY out of line...
That said, and not knowing the new powders, TAC wouldn't be bad substitute IMHO.
