I was issued an H&R M16A1 at Ft. Knox, Kentucky while attending the ROTC Basic Summer Camp (2 year program). Actually, I believe it was marked XM16E1, but that was a long time and many M16s/AR15s ago. The one thing I remember with great clarity is that it was amazingly accurate. And that we cleaned the barrels (per the instructions of our Drill Sergeant) with the bore brush on the end of a bunch of sections of cleaning rod chucked into a power drill.