My experience with APP 3F was it's powder attracting moisture while loaded in the barrel. Had to shoot the ML twice a day as a safeguard.

I recall the large clumps in the jug. If I remember correctly, those clumps were not velocity-recoverable. If you were to separate enough of the clumped powder to register the 100 grains you were normally shooting,. you wouldn't even hit target paper at 50 yards.