Evidently, the M16A2E1 did not provide enough benefit as the Army adopted the regular M16A2 in 1986. The upper receiver rail milling pattern appears to have been reused in the later Colt ACR ...

Evidently, the M16A2E1 did not provide enough benefit as the Army adopted the regular M16A2 in 1986. The upper receiver rail milling pattern appears to have been reused in the later Colt ACR ...