I ordered some R16 to try, never had any before. I think I'm going to give this R19 to my SIL to play around with and just stick to "known" temp stable powders, ha I guess I'm getting too OCD, but It can go from freezing to 80-90 degs in the Fall over here, if not in one day, in one week I've seen it. I finally got my little Kimber 84L Classic home. I had the smith send it off to "300 Below" for cryo treatment, trying to hedge my bet on stabilizing this skinny barrel, ha.set the trigger at 2 1/4 , it sure is sweet!