In my box of miscellaneous fired brass, I found I have some Remington 7.62x39 brass that uses small rifle primers. All other brands of 7.62x39 brass in that box use large rifle primers (Lapua, Winchester, PMC & some with an IK [Yugoslavia] head stamp). I resized some of them to 6.5 Grendel & found the Lapua brass might need to be neck turned. Their brass is thicker in the neck than the other brands after resizing.
The trick is growing up without growing old. -- Casey Stengal