Now you are flat out lying. Which you always do in defeat. I answered your questions all morning. You still can't tell me the differences in the lowers nor can you explain if they are the same rifle, designed for the battlefield, they would have two different lowers.
Because they are different. One was designed for civilians, the other designed under the army definition of an assault rifle for the battlefield.
The difference between the two is one has a selector that goes from safe/semi/auto. The other has safe/fire. One is branded COLT M16. The other COLT AR 15. One is branded .223 for caliber. The other 5.56. One has Model SP1.