H&K HK416 Family
The H&K HK416 is a select fire assault rifle designed and manufactured by Heckler & Koch, it fires 5.56x45. Although its design is based on the AR-15, specifically the Colt M4 Carbine, it uses a proprietary short-stroke gas piston system identical to that of the G36 Family. Thanks to this system the HK416 is better suited to sustained fire and more reliable than the M4/M16 Direct Impingement system in adverse environments. It is the standard issue service rifle for the Norwegian Armed Forces, the French Armed Forces and was the weapon used to schwack Osama Bin Laden.
The Commonwealth Joint Task Force inherited a large number of HK416 Rifles of various varieties from its member units such as Malaysian PASKAL, Singaporean SOF and Australian Special Operations Command.
H&K HK416 D10 with a Tan camo paint, held by a member of CJTF in Afghanistan.
The HK416 is a widely used and popular weapon system and as such a large variety of variants have been created to meet the many requirements of various nations. A majority of the variants consist of furniture changes and a longer/shorter barrel. The number in D10 (HK416 CQB for SMA), D14.5, D16.5 & D20 denotes the length of the barrel in inches. The longer the barrel the more inherantly accurate the rifle will be. With ACE specific barrel lengths work better with specific types of ammuniton as well, getting better or worse ballistics based off of the ammunition and barrel length used.
For example the Mk262 Ammunition is optimised for use with longer barrels getting the most velocity and accuracy with the longer barrel i.e. D16.5 & D20. The Mk318 is better optimised for shorter barrels i.e. D10 & D14.5.
There are two additional variants of the HK416 meant for dedicated roles, the M27 IAR (Infantry Automatic Rifle) and the HK416N. The M27 IAR is an automatic rifle variant of the HK416 designed for the USMC meant for sustained automatic fire, it has a heavy 16.5" Barrel which helps slow down the gain of heat during automatic fire with ACE enabled. The HK416N is a DMR variant of the HK416 designed designed specifically for the Norweigan Armed Forces, it is a further accurised version of the D16.5.