I have gathered some components to hand load for my CZ 83 in 380 auto, and did a couple of ladders with HP-38 and AA#2 using RMR 95 grain FMJ projectiles, and WSP primers, mixed brass, .990" OAL. Using published loads from both powder manufacturers for the ladders, I was surprised to find the velocity measured via the chronograph was higher than I expected for the AA#2 loads. For this powder, both the Lee and AA data suggests a starting load of 3.3 gr. and a max of 3.7, whereas the Lyman manual suggests 1.9 gr. to start and 2.9 gr. max. This is a large variance between the two sources for such a small volume charge of powder.
Using the AA published range of 3.3-3.7, I was getting velocities of about 990fps on the starting load, and up to 1060fps on the max load, vs. published velocities of 822fps for the starting load, and 934fps for the max load. I was really surprised that even the AA starting load produced velocity above the published maximum load's velocity. For comparison, the HP-38 starting load of 2.9 gr. returned about 810fps, and the 3.2 gr. max load achieved 924 fps. The AA#2 loads definitely felt snappier. All rounds with both powder cycled and functioned fine.
Does anyone have experience loading 380 with AA#2? Thoughts on the variance in published charge weights between sources? Was considering stepping down the charge weight of the AA#2 a bit to see if I could back the velocity down to align with the published velocities.