I have just gotten my 550b, First progressive press and have loaded a few hundred rounds of 10mm and 45 acp. I am now in the process of loading for my 44 mag and heres where my problems are starting. I just received a quick change kit along with the conversion kit. I am having problems with this certain powder measurer or maybe powder. I am using alliant 2400 19.0 grains. The powder bar is the small one. I am checking the weights on my rcbs chargemaster digital scale which I re-calibrated various times during this dilemma. Problem is sometimes it weighs spot on and then off by more then .4 tenths of a grain. A couple times even by 1 whole grain. Also have some powder on the shell plate which I believe might be me ( not pausing enough? ) anyways I have taken the powder funnel out and cleaned it with an alcohol pad along with most of the measurer and also used a dryer sheet to wipe the inside of the powder hopper to rid any static in there. Any other ideas???? Your help would be greatly appreciated.