Rock Island Arsenal M231 FPW (Firing Port Weapon)

History of the Rock Island Arsenal M231 FPW (Firing Port Weapon)

The M231 FPW ("Firing Port Weapon") is a heavily modified dedicated variant of the Colt M16A1 series assault rifle. Also equipped with 5.56x45mm NATO cartridges and operating on the same gas system, the M231 is designed for the crew and passengers of the US Bradley Infantry Fighting Vehicle (IFV) and can be connected to the Enemy Infantry Engagement. Design work on this product began at Rock Island Arsenal in 1972, coinciding with the introduction of a new mechanized infantry fighting vehicle that eventually became the Bradley Fighting Vehicle.

Introduced in 1980, the weapon was used in the 1991 Gulf War and the 2003 Iraq War and is still in circulation today (June 2014).

retains most of the general form and function of the M16A1, but accepts an open bolt design. A threaded section along the front end is used to thread the barrel through the available launch ports of the Bradley vehicle. The weapon can be installed in this way, or it can be dismantled and operated on the battlefield as a standalone carbine weapon. Since the gunner will be attacking through the vehicle's sight and periscope, no iron sights are fitted, although the carrying handle can be used as a fairly simple aiming reference. It is fed from the same 30-round STANAG curved detachable magazine as the M16A1.

The M231 FPW has a rate of fire of about 1,225 rounds per minute, although short bursts are usually the day's missions. The effective range is 330 yards, providing the necessary protection for infantry.

For its intended role, the M231 is intentionally compact in size - 28.25 inches in overall length and 15.6 inches in barrel.

Today, the Bradley Line has removed most of the launch ports, except for the rear-facing position, which in turn limits the tactical value of specialized weapons like the M231 FPW.

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