The Army 1st Special Forces Operational Detachment-Delta has been using the HK 416 weapon platform since early 2004 to replace their M4 carbines for a, particularly good reason.  The piston driven system design prevents combustion gases from entering the weapon’s interior.  The reduction in heat and fouling of the bolt carrier group increases the reliability of the weapon and extends the interval between stoppages. It also reduces operator cleaning time and stress on critical components, something that becomes almost an inconvenience in the field for standard AR/M4 platform users.

Take a look at the following video for a closer look at this weapon system.

*Photo courtesy of Vickers Tactical Youtube channel