Rock Island Arsenal M231 FPW (Firing Port Weapon)

Special Vehicle Carbine

United States | 1980

"The M231 Firing Port Weapon was a specialized variant of the M16A1, used by Bradley vehicle occupants through the available firing ports presented."

Authored By: Staff Writer | Last Edited: 08/15/2018 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site; No A.I. was used in the generation of this content.

The M231 FPW ("Firing Port Weapon") was a highly-modified, specialized variant of the Colt M16A1 assault rifle series. Also chambered for the 5.56x45mm NATO cartridge and operating on the same gas system, the M231 was specifically-designed for the crew and passengers of the American Bradley Infantry Fighting Vehicle (IFV), engaging enemy infantry through the available firing ports of the Bradley. Design work on the product began in 1972 by Rock Island Arsenal to coincide with the arrival of a new mechanized infantry combat vehicle - this eventually becoming the Bradley vehicle. Introduced in 1980, the weapon saw use in the 1991 Gulf War as well as the 2003 Iraq war and remains in circulation today (June 2014).

Much of the general form and function of the M16A1 was retained though an open bolt design was accepted. A threaded section along the forend was used for passing the barrel through the available firing ports of the Bradley vehicle. The weapon could be fixed in this manner or removed and operated as a stand-alone carbine weapon in-the-field. Since the gunner would be engaging through the vehicle's vision blocks and periscopes, there were no iron sights fitted though the carrying handle could be used as a rather basic aiming reference. Feeding was through the same 30-round STANAG curved detachable box magazines featured in the M16A1. The M231 FPW showcased a rate of fire of about 1,225 rounds-per-minute though short bursts were generally the call of the day. Effective range was out to 330 yards which offered the needed protection against infantry.

For its intended role, the dimensions of the M231 were purposely compact - an overall length of 28.25 inches with a barrel measuring 15.6 inches.

Today, the Bradley line has seen most of her firing ports removed save for the rear-facing positions which, in turn, has limited the tactical value of such a specialized weapon as the M231 FPW.

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Physical
The physical qualities of the Rock Island Arsenal M231 FPW (Firing Port Weapon). Information presented is strictly for general reference and should not be misconstrued as useful for hardware restoration or operation.

717 mm
28.23 in
O/A Length

396 mm
15.59 in
Barrel Length

7.34 lb
3.33 kg
Weight

Gas-Operated; Open Bolt
Action

5.56x45mm NATO
Caliber(s)

30-round detachable box magazine
Feed

None.
Sights

Performance
Performance specifications presented assume optimal operating conditions for the Rock Island Arsenal M231 FPW (Firing Port Weapon). Information presented is strictly for general reference and should not be misconstrued as useful for hardware restoration or operation.

984 ft
299.9 m | 328.0 yds
Max.Eff.Range

1,225
Rounds-Per-Minute
Rate-of-Fire

Variants
Notable series variants as part of the Rock Island Arsenal M231 FPW (Firing Port Weapon) Special Vehicle Carbine family line.

M231 FPW - Base Series Designation

Operators
Global customers who have evaluated and/or operated the Rock Island Arsenal M231 FPW (Firing Port Weapon). Nations are displayed by flag, each linked to their respective national small arms listing.

Contractor(s): Rock Island Arsenal - USA

[ United States ]

Design Qualities
Some designs are single-minded in their approach while others offer a more versatile solution to requirements.

AUTOMATIC FUNCTION

SPECIAL PURPOSE

Recognition
Some designs stand the test of time while others are doomed to never advance beyond the drawing board; let history be their judge.

Military lapel ribbon representing modern aircraft

Going Further...
The Rock Island Arsenal M231 FPW (Firing Port Weapon) Special Vehicle Carbine appears in the following collections:

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