It is. The only reason it was adopted though was because the M14 was garbage and not ready to be fielded in large numbers for troops deploying to Vietnam. The M16 was, so was procured by the Army and performed well enough(though again didnt stop retarded desk jockeys from hindering its use) the M14 was finally canceled and replaced.
Of course Army didnt skip a beat trying to replace the M16 with project spew, G11, OICW, XM8, and now finally the Sig Spear. Absolute retardation in US mil small arms world.