Been looking for years, and finally got a real M16A4 barrel. Dennis Todd finally got a few, but had to buy the whole upper. Used the same lower as before from a donor Colt's MT6400C with a Colt's fixed buttstock assy. Unlike my AR-15, M16A1, M16A2, and M4A1 upper this one is not USGI but factory direct. The M16A4 is a more recently acquired rifle, and may be some time before we see surplus USGI uppers available.
Here is the thread with pics detailing the project prior to me getting the proper upper for it:
www.ar15.com/forums/topic.html?b=3&f=118&t=228480The M16A4 was adopted Standard A in 1997 to replace the M16A2 as the standard rifle. M16A4 rifles were not delivered in large numbers to the US Army until 2001, and the Marines got their first major shipment in 2003. Army rifles are about 50/50 Colt's and FN's, while Marines are FN's.
Older "CAF" upper. Colt's went to Diemaco uppers on thier M4/A1 Carbines, not sure what upper is current on the M16A4.
Optic is a TA31F, similar optics are commonly used with Marines in Iraq. TA31 series equipt Army M16A4 rifles are also in use in Iraq in small numbers, while the M68 CCO is prevalent.
M16A4 uppers have the "T" numbers on top.
Barrel is dated 04/98, and marked C MP 5.56 NATO 1/7. Barrel does not have M4 feed ramps. I went ahead and updated the upper by replacing the peel washer with a crush washer (crush washers have been in use since 1999?).
Close up of the "F" stamp front sight base. Both the M4/A1 and the M16A4 use "F" stamped front sight bases.
Detail of bolt markings. The M means Magnetic particle inspected, the P stands for Proof fired, the V is a date code, and the C signifies Colt's. Colt's temporarily used a complicated bolt dating system during the late 90's thru late 2001. Extractor spring is the standard silver with black insert. Current delivered M4/A1 rifles have a HD gold spring and black buffer insert.