The Malfunction

About a month ago, a Soldier at Fort Knox, Kentucky made a cell phone video showing him attempting to fire his charged Product Improvement Program M4A1 while the selector lever was set halfway between the Semi and Auto detent positions. Naturally, the weapon didn’t fire.

When he rotated the selector lever completely into the detent Auto position, the weapon discharged. The process has been repeated with a weapon from a different manufacturer, but going from Safe to Semi.

As I’m sure you know, it’s not supposed to work that way. Consequently, the Army’s Tank and Automotive Command, responsible for small arms maintenance, issued two separate Safety of Use Messages (18-004 & 18-005), in conjunction with PEO Soldier’s Program Manager for Soldier Weapons to address the issue.

Interestingly, the SOUM directs Soldiers to not attempt to replicate this malfunction during live fire. Of course, they’re going to. It wouldn’t have been discovered if someone hadn’t been messing around in the first place.

Fortunately, no one was injured or killed due to this malfunction. It’s just Joe, doing what Joe does. Except now, Joe videos it.

History

The design for the M16 family of small arms is over 60 years old and the weapon itself has been issued to the US military for well over half-a-century.

In all of that time, we’ve never seen a documented case of this malfunction. Personally, I never considered that a Soldier would fail to rotate the selector lever to a functional, positive detent position. Until someone did it.

The Cause

The malfunction isn’t detected via the standard function check. However, weapons which have the issue will still will work just as they always have, so long as they are used properly. It is also important to note that this issue is not manufacturer specific, having been exhibited in both Colt and FN guns. It may also affect weapons of the other services, so they should heed the SUOMs as well.

When I first heard about it, I immediately suspected out of spec parts. Considering the Army’s efforts to upgrade its M4 and M16 fleets to the M4A1 standard, it’s plausible that they got ahold of some triggers, disconnectors, sears or selector levers that were not manufactured to tolerances called for in the Technical Data Package.

According to Army sources, upon inspection, some of the new ambidextrous selector levers have been manufactured at the edge of the spec. When combined with other parts in the same situation, tolerance stacking has combined to cause the issue. No one specific culprit is to blame.

Apparently, the Army determined that about 10% of the weapons they have inspected possess this defect. I’ve been unable to recreate the phenomenon on any of the weapons (both commercial and govt contract) I’ve had access to over the past few weeks. Still, 10% of issue weapons is an issue which must be dealt with.

TACOM SUOM #18-005 contains a more detailed function check to determine if the weapon will malfunction. Units should perform this check on all M4/16s. It is important to note, even if the issue is present, the weapon is safe to use, so long as it is used properly.

The Fix

The Army is taking additional measures to Using the full range of DOTMLPF analysis the Army considered different ways to mitigate the issue.

C-SPORTS

One, was to change the Army’s long held immediate action drill from the M4/16, called SPORTS.

Civilians have simplified the procedure to Tap-Rack-Bang, for tap the magazine to ensure it is fully seated, rack the slide to extract the round which didn’t fire and load a new round and bang to fire the weapon.

Due to these misfire, the Army has added a C to the beginning for Check as in check to make sure the weapon is on Semi or Auto.

An Updated Selector Lever

Additionally, the Army has initiated a change to the TDP for the selector lever which adds a chamfer to the face which will force the lever to snap into a fixed detent position rather than remain floating between functional detent positions.

This new version of the ambidextrous selector lever will have the same NSN and units will be authorized to swap out current selector levers for the new one, regardless of whether the malfunction is present.

Although some have called for a hands-on inspection of all of the Army’s M4/16 fleet of almost 1,000,000 weapons by a TACOM team, unit level armorers are more than capable of conduction the function checks and installing the new selector levers. There’s no reason to expend valuable resources on a TACOM inspection team.