Stamped AR lower question.

[kAnJii]

If I have a lower stamped 5.56 and one stamped .223 (both from the same company), any difference in the lowers?

If I wanted to shoot .223 in one and 5.56 in the other, any differnces that need to be done between the two? I heard 5.56 are hotter rounds and that you can shoot .223 in a 5.56 AR but not the other way around. Is the difference in the upper or barrel?

[Stanze]

If I have a lower stamped 5.56 and one stamped .223 (both from the same company), any difference in the lowers?

If I wanted to shoot .223 in one and 5.56 in the other, any differnces that need to be done between the two? I heard 5.56 are hotter rounds and that you can shoot .223 in a 5.56 AR but not the other way around. Is the difference in the upper or barrel?

No difference in your lowers other that the markings, if the round can fit in the mag well and someone makes a magazine and upper/barrel assembly, your lower can accept it regardless of what it say's on the side.

Your sentence about .223 vs. 5.56mm is accurate, the difference is the chamber in the barrel, they use the same upper.