The Army is investigating after an unintentional firing of an M4A1 carbine while its selector switch was moved between “semi” and “auto.”. The problem has affected at least 881 carbines ...

U.S. Army weapons officials have figured out the cause and ginned up a fix for a dangerous glitch in the selector switch of M4 and M4A1 carbines that could cause the weapon to fire unintentionally ...

The selector switch on the M4A1 allows the user to engage the weapon safety (“SAFE”), preventing it from firing, firing semi-automatic (“SEMI”), or firing fully automatic (“AUTO”).

Pvt. Samuel Chase, of 2nd Battalion, 5th Cavalry Regiment, 1st Armored Brigade Combat Team, 1st Cavalry Division, fires an M4 carbine during a live fire exercise. (Sgt. Jamar Marcel Pugh/Army) The ...

Both the Army and Marine Corps are checking their M4 carbines and M16 rifles for a malfunction with the selector switch that causes the weapons to fire without soldiers or Marines pulling the trigger.

Soldiers will continue to use the M4 carbine or improved M4A1 carbine as their issued weapon, as the Army has concluded the Improved Carbine competition without having selected a winner.

The M4 carbine was approved to replace it starting in 2016. The switch was driven by a need for a more compact and manageable weapon, particularly in close-quarters combat.

ANNISTON ARMY DEPOT, Ala. -- In October 2013, Anniston Army Depot began gearing up to modify M4 carbines throughout the U.S. Army. The M4 Product Improvement Program has two phases.

U.S. Marines assigned to Scout Sniper Platoon, Battalion Landing Team 3/2, 26th Marine Expeditionary Unit (MEU), conduct an M4 Carbine live-fire exercise on the flight deck of the USS Kearsarge.