Panzerschwein
member
The M16A4 was not bad. This was in late 2003 when we were issued the new rifles, through deployment ending in fall of 2004. Now all the USMC grunts run M4's transitioning to the M4A1 and the HK M27 IAR.
Our A4's were made by FN and replaced Colt M16A2's. The Colts had nicer machining on the upper and lower receivers, and notably better triggers. My best qualification score was with my brand new (like I took my rifle out of the plastic wrapper new) A4 though, probably attributable to a new barrel with a pristine throat and bore.
The Knights Armament quad rail was durable, but heavy and did not free float the barrel. The included Knights Armament rail panels were worthless and stupid. All kitted out with a sling, scout light, PEQ-2, optics, and a loaded magazine it made for a heavy bugger.
I've been tempted to build an A4'ish rifle with a 20" bbl. I would be more interested in a "modernized" A4 though. To begin with I'd ditch the non free floating quad rail and choose something a bit lighter like a Centurion or Geissele rail that have very secure repeatable mounting to an extended length barrel but. Since the .mil looks to be going M-Lok I probably would too.
For a barrel I'd love something cold hammer forged and not in the government profile, maybe a nice tapered medium contour to the gas journal, tapering to around .625" near the muzzle with a flare out for the muzzle device. The goal would be to get stiffness and heat handling ability back towards the chamber where it belongs for better accuracy, while adding little weight to the actual barrel compared to the idiot government profile. I'd even take a full medium contour like offered by Criterion barrels. I'd prefer this to be chrome lined and hammered out of CMV 4150. I would then install a Surefire Warcomp on the muzzle, I have one on my Colt SOCOM II and really like it.
I'd also ditch the ACOG, but may very well stick with Trijicon and stick a VCOG on top or some other 1-6 set up, maybe even a Leupold LCO and D-EVO.
Undecided on a fixed stock or a VLTOR A5 system, probably go A5 since it was developed to do both rifle and carbine at the behest of the USMC and it flat out works.
The only other deviation would be a Geissele SD-C trigger. I love Geissele 2 stage triggers, and like the flat faced triggers so I'd get another one for this build.
That sounds like such a cool build! A modernized A4 would be so fun to have, and would be better suited for me since where I live (Kansas) there are some loooooooooooong stretches of prairie.