I'm loading 9mm 124gr Bayou bullets with Bullseye, trying to find a load that makes IDPA power factor. I start out with a mild starting load and get around 950 FPS. I boost the load by 0.2gr, and get up to 975 fps. "Oh, cool," I say to myself, "It looks like I gain around 25fps when I bump the powder charge up by 0.2gr. I'll just bump it up another two and I'll be right around 1000fps, pretty close to Power Factor, and when the weather warms up, I'll be above the threshold easily!" So I do this, and... 1040 FPS! Somehow, that additional 0.2gr powder gave me an extra 65 fps. I'm wondering if the pressures just got high enough that the powder burned more efficiently or something.