The Army is investigating the unintentional firing of an M4A1 carbine in a Soldier made video. To produce this malfunction, the selector switch must be placed between the Semi position and the Auto position, the trigger pulled and then the selector rotated into the Auto position. While this seems serious, it is not a manipulation which should ever occur in combat.

I never saw this on the M-4A1 Carbines my unit carried and I am unable to reproduce it on any of the guns I have now. The Army takes weapons functions seriously and they are looking at every M-4A1 in the inventory.

In the past three years, the Army has converted 259,000 3-round burst M-4 Carbines into to full auto M-4A1 Carbines. The product improvement program also added a heavier barrel and ambidextrous selector switches.

The three round burst trigger was disliked by Soldiers because the cam would fire an unpredictable burst of one, two or three rounds on the first burst. Even after the first burst, if the trigger was only held for two rounds, the next burst would only fire one. With a full auto trigger, a Soldier can precisely control the number of rounds by releasing the trigger.

The condition is not detected with the normal functions check which places the selector in the three selector detents, not between them. When U.S. Army Tank-Automotive and Armaments Command small arms experts started checking around, they found 881 M-4A1 Carbines which could be made to reproduce the malfunction.

In an abundance of caution, the Army sent out a safety message on March, noting the selector switch firing, adding a function check on M-4 Carbines which have been converted to the full auto M4A1 and modifying Carbine immediate action drills.

A second safety message was released in April indicated that other Army rifles in the  M-16 family may have the same problem.

While the video below shows the installation of semi-auto selector, it is the same process on the M-4A1. It is a simple procedure which can easily be preformed by unit armorers.

The following function test is required to be performed on all M16 and M4 series rifles and carbines within 10 days or prior to live fire, whichever comes first, according to the message.

1. Ensure weapon is clear by observing the chamber, the bolt face, and magazine well. The weapon should always be pointed in a safe direction.

2. Charge the weapon, place selector lever on the safe position and pull trigger. The hammer should not drop.

3. Move the selector lever to the semi position, then move the selector to a position between semi and auto, and squeeze the trigger. The hammer should drop when the trigger is squeezed. If the hammer does not drop when the trigger is squeezed, this is a failure. Record this information and continue to the next step.

4. If the hammer does not drop, move the selector in either direction. If the hammer drops without squeezing the trigger, this is a failure. Record this information.

5. Gather information recorded from failures at steps (3) and (4) and segregate the weapon for further investigation. Contact TACOM with the weapon serial number.

6. If the weapon passes steps (3) and (4), the function check is complete.

The additional functions check is to inform Army officials of the extent of this issue and determine the number of weapons affected, the messages state.

The Army’s new adjusted Immediate Action Drill has an added first step. The steps are as follows:

1. Confirm that the selector is set to semi, auto or burst.

2. Slap upward on the magazine to make sure it is properly seated.

3. Pull the charging handle completely to the rear and hold.

4. Observe for ejection of case or cartridge, and ensure the cartridge or case is ejected and the chamber is clear.

5. Release the charging handle to feed a new round.

6. Tap the forward assist to ensure the bolt is closed.

7. Squeeze the trigger; the weapon should fire.

This is a minor problem. The experts at Army Tank-Automotive and Armaments Command are digging into these guns and making sure the selectors work. There is talk of a new selector with a more aggressive detent.

Featured photo: A Special Forces Soldier assigned to 10th Special Forces Group (Airborne) conducts advanced marksmanship drills during a training event at Panzer Kaserne, Germany, March 18, 2018. This was part of a month-long training event to evaluate team skills and readiness. (U.S. Army photo illustration by Staff Sgt. Matt Britton)