liferefugee wrote:the scale has its place, I like to use it as a checking scale for finished rounds. I use my example round (I have one for each recipe) to set the scale and then randomly check finished rounds. You may have to zero it often, at least I do just to be sure, but it has always weighed my test weight correctly. Next step is to get a set of test weights. For measuring individual loads I used a 10-10 scale though just to be sure.
Just curious, but just what is it that you think that you are measuring by weighing your finished loads as some sort of QC check? The reason I ask is shown in the following table:
Got weights to .001 gram with my Mettler balance and then converted them to .01 grains, which purists can point out isn't mathematically correct, but 2 decimal places is closer than 1 or 3.
Measured the weight of JUST 5 of two types of 45 ACP cases and bullets, to see what the max variation in grains was going to be. Obviously, if I had done 50 or 100 cases or bullets, the extreme spread would be EVEN BIGGER.
I am deliberately ignoring primer weight variability, just for the sake of simplicity, and in this case it doesn't matter at all.

Now, the Lyman Pistol manual 3rd Edition lists for Bullseye powder a min-max spread of 3.5 - 5.6 grains for the lead 200 grain cast SWC, and 3.8 - 5.3 grains for a 230 grain jacketed bullet.
As you can see, the variability of mixed headstamp 45 brass TOTALLY OBSCURES the weight of the Bullseye powder, so you could have anything from a squib load to a fairly deadly double charge and have no chance of seeing it at all!
With identical premium Hornady nickel brass cases, the variation is still 1.62 grains, which is plenty to turn a max load into a kablooey load with Bullseye powder.
With factory made Hornady XTP bullets the variation is down to .73 grains, but that's still too much variation in powder for Bullseye, so even premium factory bullets partially hide the weight of the powder.
With hand cast Lyman 200 grain SWC that I cast about 30 years ago, the variation is 1.25 grs. which compared to factory jacketed bullets, is pretty darn good considering I made them myself. Still, way too much variation to figure out from the finished load WTF the weight of the powder really is.
Bottom line, variations in the weight of a 45 case will have a very minor effect on pressure with Bullsye powder, if any.
Variations in weight of the bullet of +- 1 grain won't make diddly squat worth of difference in the pressure or velocity of the load.
Combine the above two variations, however, and you have ZERO chance of accurately knowing how much powder is in any load. Hell, you can't even tell if there IS powder in a finished round or not in this particular example!
In general this will be the way the variability will shake out, with the case and bullet partially or completely obscuring the weight of the powder, and it's the powder weight that's CRITICAL with any load.
So, what is it that you specifically accomplishing by weighing ever finished load?? You have 4 separate components (case, bullet, powder, primer), and each of them have certain statistical fluctuations in weight. How do you separate out the individual fluctuations of each component by measuring just the total weight of all 4 after the load is completed??
And no, this isn't just pointless technical jabberwocky from an old reloading nerd. In this particular example, which would be fairly common, you could easily miss a double charge of Bullseye or 231 or Titegroup in a 40 or 45 load, and we've had people in here blow a gun completely apart with what was probably a double charge.