Re: NZ Long Range Hunting
You're 100% right about ball powders varying with temperature and H50BMG being incredibly temperature stable. That is why the similar 2211 has been my favourite powder for a long time now in my big guns. Its one more variable I don't have to worry about when calculating drop making a shot while hunting. I only have to worry about the temperature affect on air density, not on muzzle velocity due to the AR powder series superb insensitivity. Using ball powders I always had an ammo temperature correction I factored in as well. But you can't beat the velocity attainable with the ball powders. I wonder how Kirby finds US869 temperature wise? I seem to remember reading he found some unexpected pressure signs out testing with it one day in the 338AM. That sort of thing used to happen to me all the time when I burnt a lot of H870 long range hunting goats, hot days and accumulated fouling when you're shooting 50 or more rounds a day saw the pressures rise considerably.
Have you tried any 869?
Email me and I'll give you my thoughts for what they're worth.