M4 Carbine

M4 transparent

(from http://www.pmulcahy.com/assault_rifles/us_assault_rifles_a-c.htm)

The M-4 is a cut down carbine version of the M-16A2. This weapon, unlike most of the M-16-based carbines and short assault rifles, can mount the M-203. The weapon was designed for paratroopers and special ops troops, to allow them to jump with their weapon uncased (for faster access during combat jumps), as well as to replace the M-9 pistol in some roles, but it has become the standard assault rifle in many other types of US units as well. The British SAS and SBS also use a large amount of M-4s, particularly the M-4A1 SOPMOD.

Operation of the M-4 is essentially the same as that of the M-16A2 (in fact, they share a receiver and its internal components), but the barrel is 14.57 inches long (officially, 14.5 inches long). The barrel is tipped with the same flash suppressor as the M-16A2, and fires on semiautomatic or three-round bursts. The stock is a four-position sliding one, with a lever on the underside of the buttstock allowing for this sliding. The M-4A1 is essentially the same weapon, but has the burst-fire mechanism replaced by a full auto setting. There is also a version of the M-4 (alternatively called the M-4E1, M-16A3 carbine, Colt Model 923, and M-4A2), which is an M-4, complete with the burst mechanism, but the carrying handle replaced with a MIL-STD-1913 rail. Another version of this carbine as the burst mechanism replaced with a full-auto setting, but I don’t know what official designations have been given to this version. In the charts below, I call them the M-4E1 and M-4A1E1.

With US special ops units using the M-4A1 variant so much, the US Navy Special Warfare Center developed the SOPMOD kit for the M-4A1 (which will also fit any of the M-4 series). The M-4A1 SOPMOD replaces the carrying handle with a MIL-STD-1913 rail, and a RIS (Rail Interface System) replaces the standard handguards, providing four more MIL-STD-1913 rails where the standard handguard was. This allows the M-4A1 SOPMOD to mount a dizzying array of accessories and optics, as well as items such as an underbarrel grenade launcher or shotgun kit. The types of accessories are limited only by the imagination of the shooter and what the mission calls for. (The player who is equipped with an M-4A1 SOPMOD may choose up to $300 of accessories for his rifle, and these are included in the cost.)

Like its parent the M-16 series, the M-4 has a designated marksman version. The 82nd Airborne and 101st Air Assault Divisions developed a Designated Marksman Carbine that is based on a flattop version of the M-4 Carbine. The M-4 DMC uses a heavy, match-quality barrel, and the carrying handle is replaced by a MIL-STD-1913 rail which extends from the receiver to the front sight post. No rear iron sights are normally used, but can be added to the rail. The front sight can also be removed as required. The barrel is 18 inches long and is free-floating, but uses a 1:8 twist to accommodate both standard SS-109 ammunition and match-quality rounds, and is made from stainless steel. The trigger and fire mechanism has been replaced by a two-stage match trigger, and is (like her big sisters the US Army SDM-R and USMC SAM-R) a semiautomatic-only weapon. On the handguards is mounted a Harris S-L light bipod, adjustable for height and cant. The M-4-based version is identical except for the 14.5-inch barrel. The cost of these weapons below include a compact telescopic sight.

Designation Ammunition Load Magazines Barter
M-4/M-4E1 5.56mm NATO 2.52 kg 20, 30 $570
M-4A1/M-4A1E1 5.56mm NATO 2.54 kg 20, 30 $575
M-4A1 SOPMOD 5.56mm NATO 2.6 kg (base) 20, 30 $878
M-4E1 DMC 5.56mm NATO 4.42 kg 10, 20, 30 $1148
Weapon ROF Damage Pen Bulk SS Burst Range
M-4/M-4E1 3 3 1-Nil 4/5 3 4 34
M-4A1/M-4A1E1 5 3 1-Nil 4/5 3 7 34
M-4A1 SOPMOD 5 3 1-Nil 4/5 3 7 38
M-4E1 DMC SA 3 1-Nil 4/5 2 Nil 37
With Bipod SA 3 1-Nil 4/5 1 Nil 48

M4 Carbine

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