Following on from a recent article about the modern DEVGRU HK416D, Jack – F17 of the legendary Gray Fox – took a few pics to help illustrate the known evolution of the upper; which is really interesting to the casual observer and very useful to clone builders.

The evolution starts from the top, with the OG HK416D quad rail upper. It then moves to the iconic Remington RAHG. Finally, the most modern era is depicted with a bang up to date Midwest Industries HK M-LOK rail.

As usual, Jack is using RS parts where possible, including upper receivers per se – optimised for the Systema PTW.

Although the rails provide an excellent shorthand for the changes, other parts and accessories have evolved as well.

Notable is the BE Meyers flash hider on the early upper and the AAC flash hider/can combo on the later uppers.

Also of note is the steel ejection port cover of the early upper. Heckler & Koch started shipping polymer dust covers with the 2007 version of the HK416D. This move coincided with the adoption of the slim profile barrel.

The original thick/bull barrel, which was shipped with the HK416D pre-2007, was disliked by users. The weight it added to the front end was seen as excessive. Consequently, some pre-2007 weapons were retrofitted with the newer, slim profile barrel.

Incidentally, the term ‘SOCOM barrel’ is used for the original, discontinued barrel…even though SOCOM customers now use the slim profile barrel.

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