05 December 2011
FWS Armory: What Gun Killed Osama Bin Laden?
The easy answer is that this German-made assault rifle was Hecker & Koch's attempt to redevelop the 40+ year old American M16 system for the demands of these new 21st century wars, and hopefully get the contract to rearm the US military.
H&K 416 links:
All about the sorted history of the M4
The Colt M4 CQBR (MK 18 Mod 0)
For the same reasons listed above, I doubt that UBL was sent packing, via a sidearm, and if he was, I'm more certain it was P226 and not the newly acquired H&K 45C.
In September of 2010, NAVSPECWAR adopted the .45 ACP handgun, and according to some research, it replaced the H&K Mark 23 SOCOM Offensive pistol that was adopted in 1996.
H&K Mark 23 SOCOM