After reading about humidity's pretty drastic affect on velocity and then hearing Bryan Litz on a podcast talking about it, I started thinking maybe it was a factor I had overlooked for my PRS ammo.
My reloading room is almost always very close to 30% humidity. This is lower than almost every place I travel to by a significant amount. After travelling to Tennessee in December and having my ammo exposed to 80%+ humidity for several days I had a slight drop in velocity that cost me a few points on day 3 of the AG cup. After returning home and having my ammo sitting on a shelf in the ~30% humidity for about a week I went to the range and discovered that my velocity was back up to where it was in the first 2 days of the AG cup.
Here is the question I plan to test: Does the powder in loaded ammo subjected to a different humidity level acclimate to that new humidity level? If so, how long does the ammo have to be exposed before the change is significant for PRS purposes?
I have 2 sets of ammo loaded and in sealed clear plastic ammo boxes. One set with a 32% humidity pack (closely matches my reloading conditions and the humidity the Varget was acclimated to) and another set with 62% humidity control pack. I have humidity meters in both that are visible through the plastic. I'm going to shoot both sets of ammo approximately 52 hours after I loaded them and sealed them in the boxes. If they both shoot very close to the same average velocity I probably don't have to worry about trying to control humidity while travelling to higher humidity areas for matches.
Either way I'll report back and update this thread. Any predictions?
My reloading room is almost always very close to 30% humidity. This is lower than almost every place I travel to by a significant amount. After travelling to Tennessee in December and having my ammo exposed to 80%+ humidity for several days I had a slight drop in velocity that cost me a few points on day 3 of the AG cup. After returning home and having my ammo sitting on a shelf in the ~30% humidity for about a week I went to the range and discovered that my velocity was back up to where it was in the first 2 days of the AG cup.
Here is the question I plan to test: Does the powder in loaded ammo subjected to a different humidity level acclimate to that new humidity level? If so, how long does the ammo have to be exposed before the change is significant for PRS purposes?
I have 2 sets of ammo loaded and in sealed clear plastic ammo boxes. One set with a 32% humidity pack (closely matches my reloading conditions and the humidity the Varget was acclimated to) and another set with 62% humidity control pack. I have humidity meters in both that are visible through the plastic. I'm going to shoot both sets of ammo approximately 52 hours after I loaded them and sealed them in the boxes. If they both shoot very close to the same average velocity I probably don't have to worry about trying to control humidity while travelling to higher humidity areas for matches.
Either way I'll report back and update this thread. Any predictions?
