Jim--
I agree. I made the mistake of buying M80 surplus ball bullets thinking they weight the same. When I started to check the weights. The weights varied from 145 grains to 150.2 grains in a batch of 1,000 bullets. When I researched why the wide variation? It turns out, that at least the US Military spec allows for this variation in weights to make the bullets dispersion better in the MGs. Given my time to weight the bullets it was not worth the trouble. After the that I bulked by commercial bullets, Since I use my ammo in some belt-feds. I factory crimp all of ammo that will be used in a semi-auto except my match stuff.
--fjruple