Sorry for the delayed report. Finally back at it with this 308 setup.
I had a chance to run about 25 rounds through the Stalker 308 Win barrel, mated to my Optima Elite receiver. After I got the Leupold M8-3x dialed in, I put 10 shots into a 1.5" group at 75 yards with 42.5 grains of IMR 4895 under a Hornady 150gr Interlock SP. That's about the best I can manage with the trigger on this receiver. It's crisp, but the break is still a bit stiff. Need to work on lightening it.
I also tried some 155 grain hard cast/gas checked rounds from a Lee mold (the 312-155...Lee's 7.62x39 mold, sized .309). 40 grains of IMR 4895. Didn't group well at all. Probably pushing them too hard. I'm going to dial back that load a few grains and try again. I'm hoping to use these bullets for a mild 308 Win deer load for my son and his cousins to use.
Overall, pleased with the barrel and the fact that it works with my Optima Elite receiver.