Contrary to popular myth the APP powders do not "suck moisture". They simply clump. Shake the can and the clumps break up.
A gentleman on another site knows more about blackpowder and the substitutes than anyone else alive. He has extensively tested the APP powders. His tests show APP powders to be no more hygroscopic than blackpowder or the other BP substitutes.
Last edited by falcon; 10-10-2015 at 11:15 AM.