But 17 is not alone in this: Another excellent, modern double-based powder for 140s in the 7x57 is Ramshot Big Game, which is widely known as a "wonder powder" for the 7mm-08. It works just as well in the 7x57, and in my experience is more temperature resistant then RL-17. In my last 7x57, made by the company with the short-throated reamer, 48.5 grains of Big Game resulted in just under 2900 fps from the 21-inch barrel with the 139-grain Hornady Spire Point Interlock, and excellent accuracy.
John:
I was looking back through the 7-08/7x57 chapter in Gack I and noticed that with just about every rifle and load for the 139-gr Hornady ILSP you were getting sub-MOA groups, which was much more consistent than any other bullet except the 140-grain NPT. Even then, the IL groups were a bit smaller. Did you ever have a 7x57 or 7-08 that wouldn't shoot the IL into sub-MOA groups? And do you find that they're more consistent at the higher end of the velocity scale or somewhere below? The loads in Gack I look pretty near the top.
Thanks
RM
