I have been wanting to develop a load for my 41 mag model 57, AA9 has for some reason become spotty in my area, it is sooty and I have not really liked the performance. My LGS had a nice shipment of 2400 so, stocked up a bit. Did a bit of a ladder test, and have have settled on 17.5 grs. Over the chronograph, my load of 17.5 , under a 215 gr SWCBB acme bullet, starline brass and fed primer, did an average of 1340 fps. About perfect, to my way of thinking, the weird part, was 18 grs, and then 18.5 grs, gave chronograph reading, under the 1340, in fact, one cartridge of 18.5 grs, gave a velocity of 1302. Has anyone had this happen?