My powder puff loads failed to reliably cycle the action. The cool weather probably contributed to this. In the hot (for the Seattle area) summer the loads cycled the same gun just fine. I think I need to add another 0.1 of a grain to the load to make sure they work in the cooler weather.
I tested my new loads today. They worked great. I tested them in two different guns and also tested the old load. Both guns cycled the action without a problem with the new loads. The old loads had a few problems in the cool weather.
The 0.1 grain increase in charge also decreased the standard deviation:
|Gun||Bullet Weight||Powder charge||Mean velocity||PF||Sdev||ES||Min||Max|
The group size was significantly smaller as well. This may have been because of the decreased standard deviation. A 140 PF is still very pleasant in a .40 S&W gun.
The bullets were polymer coated lead bullets. The powder was Hodgdon Clays.