Originally Posted by 1100 Remington Man
Has anyone tested Alliant powders for temp sensitivity ? Or IMR powder ?
Those powder company folks probably have. Contact them then ask about it. If they have, their data's the best on actual issues.
Has anybody "testing" ammo by shooting it actually measured the temperature of the powder in the cartridge when it shoots the bullet out? I doubt it's the same as the ambient air temperature; most likely warmer in cool/cold weather. And one must shoot the chambered round within 1 second of closing the bolt on it so a warm/hot barrel doesn't heat up the case and the powder while it's in the chamber.
I doubt a 25 to 75 degree F change in powder temperature would shoot bullets close enough to the same muzzle velocity to have the same drop at 1000 yards with the same ambient temperature for both the bullet goes through. Note cold air has more density than hot air, so a bullet leaving at the same speed in each will drop more in the cold air than the hot air. And the 25 to 75 degree F powder temperature used in the same air temperature will end up with more drop at 1000 yards with the colder powder. If air and powder temperature were the same, the cold powder in cold air would cause even more bullet drop; less energy plus more dense air equals more bullet drop.