I have an RCBS digital mini scale that came with my kit and I use it for reloading precision 223 ammo. I am still new to reloading but seem to be getting variations on my digital scale of more than .5 of a grain at times. Also my zero seems to vary as well, sometimes showing .3+ when I have my pan zero set. How many grains does it take before I see a noticeable difference in accuracy? I'm nowhere near max loads so I know I'm safe, however I want to make the most consistent ammunition possible. What are good inexpensive digital scales that I can rely on? Also are there any good techniques in using these scales?