mine isn't the 50, but the 100 - the big brother and i only use it to check if there's a powder charge or not- i still use my old beam balance for measuring powder- as for bullets, i take what the manufacturer says they are,and when i have measured, they've been pretty close- 178-182 grains for a 180- and that could be air pressure, or a bunch of stuff- mine was only 30 bucks us and wasn't worth sending back if there was anything wrong with it- those 123 grain bullets sound like warsaw pact stuff, and i'd also verify with a beam balance before using- in other words, basically i use the beam for everything and the digital for checking only- the other thing i would point out is that when you calibrate, don't just stick the weight on the scale and zero- you have to remember your pan/container weighs something too ( my brass pan for the beam weighs a good 10 grains)
there are aslo very serious variations between brass manufacturers, and even cases will varyin weight in lot
you have 3 variables, bullets, cases, and powder charge, so you establish a high and low range for a known case lot and anything outside the norm, you pull