That’s where Superformance comes in. Fired 2850+ rounds though my MPA barreled Curtis. shooting 130 Berger VLD’s at the very bottom of the loading chart. (6.5 CM to be specific). No fouling, single digit SD’s and accuracy that no other rifle I have ever owned shot more accurately. No fouling, nothing. I only pulled the barrel off because I was it had become my backup rifle and was tired of loading two separate groups of rounds for matches.
44 Grains Superformance, 130 grain Berger VLD’s, CCI BR4 primers Lapua SP brass. It shot tighter groups at 300 than just about everything else I owned shot at 100.
I too use Varget in my GT’s. But at my load density, I am getting good enough accuracy, good SD’s and no major pressure signs. But with the cost of Varget, and a good stock of Superformance on hand, I may go back and give it a try in the GT. Down to one 8 pound keg and at $450 for another, it’s getting serious.