[tunabreath]

Just a note for people who figure that the Hk416 is so much better than the M4 because it's more reliable, I suggest you look at the extreme dust conditions reliability test again.

ZOMG, the 10 M4s had 4 times the number of stoppages compared to the 10 416s! But how much is 4 times?
The stoppage percentages for the 416 were 0.3883%, and for the M4, 1.47%
Ok, one and a half in a hundred seems pretty bad eh?
Note that the extreme conditions test really was EXTREME, as in a hell of a lot more than any rifle should be subjected to in service (if it manages to get that must dust, there's more wrong than just the rifle). These rifles fired 600 rounds each before cleaning. The average combat loadout is what? About half that? The rifles were cleaned then HEAVILY lubed before going back into the dust chamber. They are purposely TRYING to make these rifles fail, to see their limits. They are comparing the engineering of the guns, NOT their effectiveness in the hands of a soldier.
An M4 in service is going to see FAR less than 1.5% failure rates.
I expect that even if you were to replace every single M4 in service with an Hk416, not a single thing would change in the daily life of your average soldier, beyond having to learn how to clean/clear the new guns.

I agree with the governments in question's general consensus of waiting for something more revolutionary.
*just another thing, it's not like the Hk416 is the best option. There are plenty of similar upper conversions, pretty much all of them being less expensive. I keep hearing really good things about the respective Patriot Ordnance Factory upper.