Sometime back I did some dealing and received a few primed brass. Being that they were 7.62x39mm and were new, my bullets would seat in the brass but they had little neck tension holding them in. A .310 diameter bullet needs the .3065 expander ball used in the sizing die so a .310 diameter bullet will seat and hold properly.
After resizing and punching out the new primers in the brass, I proceeded to reseat them in some brass I had marked with a sharpie marker so as to designate they were different than the rest. I loaded 10 rounds like this and fired 5 of them them in a slow sequence in my mini-thirty. Examined the cases and nothing seemed a problem so I rapid fired the 5 remaining with no problems either. Seems you can actually use these primers if needed. Don't know why you would, but it is possible.
I know I could have tried resizing in various other ways, but I wanted to try that experiment. The primers appeared to be CCI.
I still wonder why that larger expander ball is included with the Lee dieset. I think I'm going to polish mine down so as to be able to use a .308 bullet if necessary.
