Re: Weighing components
A 15 gr variance is a whole lot of variance. It's been a while since I weighed some loaded rounds, but I remember them to be well within 2 or 3 gr. Your powder should be within .1 gr and bullets within .5 gr. I used to weigh brass, but like Boss Hoss said, I don't see much point in it for the reason he said. However, when I did measure them, they were usually within 1 - 2 gr.
I would recheck your cartridge weights on a balance beam scale. If I had rounds that were more than 3 or 4 gr off, I would be concerned.
I do separate my bullets into two groups, the heavier ones and the lighter ones. The extreme few on either side I use for fowlers. Some guys separate by bearing surface which makes sense.
I think the most critical measurement is the powder. I try to get it down to the kernel.