Scales, repeatability and accuracy.
I started with two different beam balances, one oil damped and one magnetic. I added one of those cheap Lee scales and damned if it wasn't the most consistent!
As I shoot long range BR, I wanted the most consistent load I could get. So, I got a Gempro and it is indeed a very nice balance for the money. But, I didn't like the lack of consistency (that word again) in the tare reading. So, I took a gamble and bought an old Ohaus TS200 on ebay.
So, I started with beam balances, moved on to a strain gauge balance (GemPro) and finally gravitated to a Magnetic Force Restoration balance. And, I am happy.
Summaries: The Ohaus is no better or no worse than the GD503 or the latest $500-$1000 balance. They all have 1 mg resolution and 1mg accuracy and superb stability. By the way, 1 mg is about 0.015 gn. My balance reads in grams or grains, but on grains, it truncates to 0.02gn steps in least significant digit so I weigh my loads in grams for 0.015gn equivalent accuracy. So much for the consistency I wanted, all these balances offer 1mg repeatability and accuracy.
So, what about accuracy? I really don't care about accuracy as long as I get repeatability. Instead of buying a high quality 100g and 200g mass to use for caliberation that must be handled with gloves and stored in a temp constant environment, I had some masses with accuracy of 3mg for a 100g weight. I took two 100g weights and weighed them on my balance. I took the heaviest one and sanded the bottom with 400 grit paper till they both weighed exactly the same. Now I have two 100gram masses to NORM'S accuracy and I use them for caliberation.
And, my velocity sd and ES did improve!. Even better when I started matching bullet seating force!