HK 416P

The HK 416P is an assault rifle designed and manufactured by H&K. It uses the AR-15 platform, originally conceived as an improvement to the Colt M4 carbine family issued to the U.S. military, with the notable inclusion of an HK-proprietary short-stroke gas piston system derived from the Heckler & Koch G36. The 416P variant is a specialised model used by the Preachers.

Design details
The HK 416P uses the same HK-proprietary short-stroke gas system derived from the HK G36, forgoing the direct impingement gas system standard in AR-15 rifles. The HK G36 gas system was in turn partially derived from the AR-18 assault rifle designed in 1963. The HK system uses a short-stroke piston driving an operating rod to force the bolt carrier to the rear. This design prevents combustion gases from entering the weapon's interior, a shortcoming with direct impingement systems. 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.

The 416P is equipped with a proprietary accessory rail forearm with MIL-STD-1913 rails on all four sides. This allows most current accessories, used on M4/M16-type weapons, to be fitted to the 416P. The rail forearm can be installed and removed without tools by using the bolt locking lug as the screwdriver. The rail forearm is "free-floating" and does not contact the barrel, improving accuracy.

The 416P has an adjustable multi-position telescopic butt stock, offering six different lengths of pull. The shoulder pad can be either convex or concave and the stock features a storage space for maintenance accessories, spare electrical batteries or other small kit items.

The 416P's barrel is cold hammer-forged with a 20,000-round service life and features a 6 grooves 178 mm (7 in) right hand twist. The cold hammer-forging process provides a stronger barrel for greater safety in case of an obstructed bore or for extended firing sessions. Modifications for an over-the-beach (OTB) capability such as drainage holes in the bolt carrier and buffer system are available; enabling the 416P to be fired safely after being submerged in water.