Assad, that is a good article. The advantage mentioned was heat and gasses in the chamber area. More critical concerns was sand.
Two statements stood out for me.
"The M4 is the highest-rated weapon by Soldiers in combat, according to the Directorate of Combat Development, Ft. Benning, Ga. In December 2006, the Center for Naval Analysis conducted a “Soldiers’ Perspective on Small Arms in Combat” survey. Their poll of over 2,600 Soldiers reported overwhelming satisfaction with the M4. The survey included serviceability and usefulness in completing assigned missions in Iraq and Afghanistan.”
"“We are not saying the [M4 and M16 are] bad,” said “The issue for me is do our soldiers have the best rifle in their hands…. The fact of the matter is that technology changes every 10 or 15 years and we should be changing with it. And that has not been our case. We have been sitting on this thing for far too long.”
It was also mentioned keeping it clean while one the move. Well my experience and you can ask any other RVN Bush Marine, that is what was our daily lives. We did not have a base that we operated out of. We were mostly always in the bush. Rain, Mud, Dust, ect. That point, was meaningless for me. I don't think my Gunny would accepted either.