Update. I ended up using Lil' Gun powder, for my sub loads with the hornady 150gr fmj/bt. I managed to get MOA accuracy, and consistent speeds of 1,050fps with 8.5gr., Winchester brass, Remington 7½ primers,and base to give length of 1.500".
Also, if anyone is interested, I found a hunting load with Hornady 125gr SST, using 19.1gr of IMR-4227, Win brass, and Remington 7½ primers, gives very consistent speeds of 1,980fps, and single digit SD. This is a compressed load, and over Hornady published maximum, so if you use it, start low and work up to it.
Thanks again for all the suggestions!