Big Game data show velocity for max charge (40.6 gr) as 2689 f/s with a 142 Sierra HPBT MK. Hunter data show with a max charge (45.7 gr) a velocity of 2761 f/s with the same bullet.
I did the Expanded 10 Shot Load Development test using Hunter with 143 gr ELD-X bullets. I stopped the top load range at 45.0 gr rather than use 45.7 max charge because I was using a different bullet that was also heaver than the Sierra used by Ramshot. Results for my top three data points is 44.4 gr = 2732 f/s; 44.7 gr = 2748 f/s; 45.0 gr = 2827 f/s. The primer on the 45.0 gr load is flattened but there is no extrusion into the fireing pin hole, no marks on the case head, and bolt opening was normal. Temperature was 55*.
I have loaded extensively for black powder cartridge rifles but not so much for smokeless rifles...so my question is should I consider 45.0 as max? I really think my most accurate loads will be around 44.4- 44.7 gr. Your thoughts?
