M4A1 M render
The M4A1 carbine with a Marksman Scope
Vital statistics
Name M4A1
Faction USMC
Type Carbine rifle
Fire Mode Auto/Semi
Caliber 5.56mm x 45mm NATO
Magazine Size 30+1
Range 400m
Damage Medium (High with AP rounds)
Used By All USMC classes

The M4A1 is a USMC infantry rifle in Operation Flashpoint: Red River, and the default primary weapon for the Grenadier class.


The M4 carbine rifle was originally developed by the United States Marine Corps as a shortened, three-round-burst variant of the M16A3 rifle. Later, the M4 was adapted to fully-automatic fire instead of burst fire with the M4A1, and the original, non-removable carrying-handle iron sights were replaced with a rail system, like the one present on the M16A4 rifle, which allows the iron sights to be removed to mount alternate optics in a simpler and more ergonomic configuration than the older M4 and M16 rifles.


The M4A1 uses the standard 5.56mm x 45mm NATO intermediate rifle round (known in non-military rifles as the .223 Remington), the same round used in the M16 and M249, and similar to the PLA intermediate round, the 5.8mm x 42mm. The M4A1 boasts a shorter barrel than the M16, allowing for greater mobility for close-quarters combat, but sacrificing long-range accuracy. The M4A1 also features fully-automatic fire, instead of the three-round-burst mode on the M16 rifle, though both rifles feature a semi-automatic fire mode.


The M4A1, like the M16A4, features the full spectrum of available attachments in the game.

  • M4A1 A - M4A1 with an M203 underbarrel grenade launcher. (default for Grenadier class)
  • M4A1 SUP - M4A1 with a flash/sound suppressor.
  • M4A1 CQB - M4A1 with an EOTech-style holographic sight (default for Grenadier class)
  • M4A1 RDS - M4A1 with an Aimpoint-style red dot sight
  • M4A1 M - M4A1 with a Trijicon ACOG-style marksman scope
  • M4A1 SN - M4A1 with a Leupold-style sniper scope
  • M4A1 NO - M4A1 with an infrared thermal night-optic scope


  • The M4 and M4A1 rifles are not technically the standard assault rifle of the Marines, however, many Marines, and even soldiers in other branches of the military, are issued M4A1 rifles, due primarily to their close-quarters advantage and slightly lighter weight, with little loss of long-range accuracy.


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