Looking at the case capacities confirms what I have thought for a long time, that the various 5.56 cases can pretty much be mixed, which they are if you buy comm'l reloads. In a real good varmint rifle, you MIGHT be able to notice a difference in group size. I have a kitchen trash can full of 5.56 brass that I've picked up at the range, almost all of it is never reloaded LC/WCC/IMI brass cause the primers are crimped in. I have never bought brass for one obviously.
