over the years I have noticed when all of the ar15 guns fire and you eject the next cartridge by hand without firing it, there is a little dent in the center of the cartridge primer from the floating firing pin. Over time I have moved away from federal primers as people always claim they are soft and will slam fire in an ar, not seen it but others here won't use them. So CCI is all I use now in those guns, and its good to know that you can substitute a small rifle magnum primer for a small rifle primer, that knowledge might come in handy someday.
their new CFE BLK looks interesting as well, I see they have a 6.8spc load for it.
