I am an old guy, so I know that no one liked the M16
initially for combat. The US army had the M14 ( 7.62 NATO ) and were very impressed with the performance. When they introduced the M 16 in quantity, lots of problems with jams, stovepipes, failure to fire.
Some of the bodies of GI's collected after fire fights had a useless black toy rifle lying nearby that had experienced some sort of failure.
I know that the black rifles have had multiple improvements since the 60's and 70's, but the overly complicated gas system makes less sense to me than a direct gas piston, such as the AK or the Mini 14 or the famous M 14.
If I absolutely had to go to combat at my advanced age, I would have to choose the AK platform for sheer reliability.
The AK and AR pattern rifles are the two most common rifle in military service today. The AK has the most widespread use. I prefer the AR for the accuracy, weight, ergonomics, and faster magazine changes myself.
I remember reading awhile back the AK platform has been the most produced firearm ever.
That is a "fact". I also prefer the AR platform for the reasons given. The early M16 issues were do to design changes and powder changes set by the Ordnance Division of the day. Had they left the design intact, many soldiers would have come home. It was a pissing contest between the Military brass and Kennedy's wizz kids.
round for most uses, and the AR platform has been improved ( or perhaps returned to Eugene Stoner's original concept ).
My active military friends in Iraq like the AR platform, but would like an arm that would engage a target at a greater distance. Not sure I understand that thought, as they have the SAW and the snipers still shoot .308 ( or bigger)
All I can give you is my limited military experience, and I found the M16 hard to keep clean in a dirty environment. I lost a lot of confidence in the Colt made military firearm I carried. My Sergeant did remind us - often - that all our equipment came from the lowest bidder!
During the Vietnam war the Australian infantry were initially armed with the GPMG M60, the Australian designed and manufactured 9mm Owen gun (SMG) and the L1A1 SLR, semi-auto rifle in 7.62 Nato - a slightly modiifed semi-auto only version of the Belgium FN-FAL produced in Australia utilising a 20rd mag.
The Owen gun later gave way to the M16 but the SLR remained our main battle rifle throughout the conflict. It was cherished by the troops and gave an honest account of itself. Accurate, reliable, hard-hitting, easy to maintain and shoot.
I daresay many US veterans feel the same way about the M14. Old flames are never forgotten.
The SLR eventually gave way to the tupperware Steyr AUG in 5.56 Nato and is currently issued to all troops, with the exception of the SAS who always appear to be carrying M4s (says a lot). The standard sidearm was, and is today, the Browning Hi- power in 9mm.
IMHO the SLR was one of the best main battle rifles of my military era (69/70) and I would gladly use it again today - but this time with an optical sight and the heavy barrel usually fitted to the L2A2 (unsuccessful full Auto, 30rd heavy barrel, Bipod model).
Handles nicely, integral optic sight and easy to train new shooters with. However those I have spoken with in the military claim they don't handle sustained fire too well, nor sandy, dusty environments.
I have no personal experience with the Steyr other than handling one, but that's what the troopies tell me.