Have recently acquired a No1S in 7X57 (a "new to me" cartridge.) I got a couple of boxes of 140 NBTs and started looking for some powder locally. I wanted 4350 or Big Game, both of which I'd seen locally recently, but which have since disappeared. Okay plan B: I picked up a pound of StaBALL 6.5 which looks good on paper and which I'd kind of been wanting to try in the 6.5X55 anyway, and started experimenting with a new-to-me powder in a new-to-me chambering. Started out with brand new Norma cases, CCI 250 primers. Hodgdon shows a max load of 47.5 grains for 2714 fps @ 45,700 CUP. As a reference, they show a max of 48.5 in the 7-08 for 2976 @ 59,300 CUP. I figured that 2900 was a good target speed and that I might need a little more than 48.5 in the slightly larger capacity 7X57 case, but I'd be happy with 2800 from the 22" barrel with good accuracy. I started out with three loads, five cartridges each, of 47.5 gr, 48 gr, and 48.5 gr to try. At the range, I got 5 shot averages of 2634, 2682, and 2708 with big extreme spreads and SD's. (Yes, I know all about statistically insignificant sample size, etc, etc, just saying...)
Accuracy was about as bad as one would expect with those inconsistent speeds, but very encouraging in that it indicated I can probably expect really good accuracy if I develop good, consistent loads.
Has anyone had much experience with StaBALL 6.5 in 7X57 or similar cases? On paper it looks like it should be a stellar performer in the moderate capacity cases like 7X57, 7-08, 6.5X55 and 6.5 C. I haven't seen much mention of it though and have seemed to recall a few vague rumors about it getting kind of squirrely in the general vicinity of maximum loads.
Glad to hear your thoughts.
