Two weeks ago my Charge Master 1500 wouldn't go on after 10 years of excellent service. Ordered the Hornady Auto charge unit, didn't use most of the features that came with the Charge Master. After receiving the Hornady unit, I opened up the RCBS scale nothing looked loose or shorted out, put it back together worked just as good as new. Now I measure my IMR 4064 using the RCBS to load to 41.5 gr. & check with the Hornady. Both scales are rated +/- .1 gr. There is a range difference from in the scales from the beginning of 41.5 to the end of 41.5. I now go with the steady 41.5 registered on both. Using one scale there could be a difference as much as 4 kernels up or down. When the company's say +/- 1gr. I thought if its minus 1 tenth that's 41.4 if its plus that's 41.6 plus the range difference. How accurate are they? Or am I just picking haired.
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Auto Powder Scales
- Thread starter cw308
- Start date
I reject any load I work up that does not stay at the same point of impact with at least a 1.5% span in charge weight (i.e., ±0.75%). I know that changes in shooting conditions, or due to powder packing down from transportation vibration, will make the pressure vary at least that much anyway.
I've pulled bullets from the highly respected Federal GM308 match loads with 168 grain Sierra MatchKing bullets, and the charge has been 43.5 grains ±0.2 grains of 4064, and that stuff has won many matches, as the name implies. One of the best loads I ever had was with Brigadier 3031 in the 308 with the 155 grain SMK. It would go from 40.5 to 43.0 grains with no shift in POI. That's almost ±3%. Unfortunately, the plant in Scotland that made that powder burned down and was not rebuilt. But such a load, if you find one, is essentially immune to most practical changes shooting conditions.
So the bottom line is, do sub tenths of a grain powder weight variations matter? Not that I can tell. But I wouldn't trust a load touchy enough to let me detect that small difference if I had one. I would reject it and move on.
I've pulled bullets from the highly respected Federal GM308 match loads with 168 grain Sierra MatchKing bullets, and the charge has been 43.5 grains ±0.2 grains of 4064, and that stuff has won many matches, as the name implies. One of the best loads I ever had was with Brigadier 3031 in the 308 with the 155 grain SMK. It would go from 40.5 to 43.0 grains with no shift in POI. That's almost ±3%. Unfortunately, the plant in Scotland that made that powder burned down and was not rebuilt. But such a load, if you find one, is essentially immune to most practical changes shooting conditions.
So the bottom line is, do sub tenths of a grain powder weight variations matter? Not that I can tell. But I wouldn't trust a load touchy enough to let me detect that small difference if I had one. I would reject it and move on.
Unclenick, thank you. I'm shooting a Rem. 700 308 cal. using 41.5 gr of IMR 4064 under Sierra 168gr.HPBT bullet & A-Max 168gr. Both are grouping very good at 200 yards. I was surprised at the auto scale weight fluctuations between both the RCBS & Hornady. Using both scales I go with the happy medium. Thanks again for your input.