I was using Ramshot Xterminator. 23.5gr under the 77gr, 24.5gr under the 75gr
Maybe not the optimum powder, but I use it with the 53gr mostly. Seems to do ok with the 75/77, but I didn't chrono it today. I've ran some of the XTerm fueled 75s through the 1/7 twist 14.7" carbine, they were hitting about 1.25" at 100 yards.
