As I said in an earlier post, there is no meaningful variation in internal volume for .223 and 5.56 across all headstamps. I found 5.56 cases (of different headstamp) with less and more volume than all the various headstamp .223 cases I looked at. This means for plinking ammo. Find a safe load and don’t bother sorting. For precision loads, stick to one headstamp.

When I make .308/7.62x51 plinking loads, I load the 7.62 cases with 10% less because they have “generally” 10% less internal volume, due to greater thickness in the base of the case.

I use the same dies for 5.56/.223 and I use the same dies for .308/7.62x51.