Fer cryin out loud, buy a check weight set!
http://www.midwayusa.com/viewProduct...tNumber=212586
Sending for and getting the check weight set, $35.00/with shipping
Using the set to determine if your scale is accurate, no cost.
Confidence that your powder charges are right on,,,,
PRICELESS!
I bought that exact set 5 years ago. Ya know something, it doesn't wear out. It don't bother you while it sits on your shelf. But if you suspect that the powder charge you just dumped on the scale, it's right there to verify the scale is right on.
I've been using a RCBS/pact digital powder pro scale for the last 15 years. It's never failed me, and each time I use the check weights, it's right on. I have a simple lee balance beam scale for back-up if the power fails, it too is right on----IF you want the aggravation of getting it set!