https://www.military.com/kitup...ter-m4a1-mishap.html

Army Updates Functions Check, Malfunction Drill After M4A1 Mishap

Military.com
30 May 2018
By Matthew Cox

U.S. Army weapons officials recently sent two safety messages to all services updating the functions check and immediate action drill for the M4A1 carbine after a soldier experienced an unexplained, unintended discharge.

The incident occurred in late March at Fort Knox, Kentucky, involving an M4 that had been converted to an M4A1 through the product improvement program, or PIP, according to the safety messages.

"The operator pulled the trigger with the selector switch between the semi and auto detents (outside of detent). The weapon did not fire when the operator pulled the trigger and instead fired when the selector was moved further," according to the messages.

No one was injured in the incident. U.S. Army Tank-automotive and Armaments Command, or TACOM, issued Safety of Use messages in March and April to address the issue.

Once used exclusively by U.S. special operations forces, the M4A1 is now the Army's primary individual weapon. It features a full-automatic setting instead of the burst setting on standard M4s used by other services.

The recent TACOM messages, however, are directed at all M4 and M4A1 carbines as well as all M16A2s, M16A3 and M16A4s in the Pentagon's inventory.

In addition to TACOM, the Army's Armament Research, Development and Engineering Center, or ARDEC, and Project Manager Soldier Weapons are investigating the incident, the messages state.

ARDEC officials are working a detailed fault tree analysis to find the cause. A sample of failed weapons is being disassembled, and a dimensional analysis is ongoing, officials said. Simulation and modeling of weapon components and tolerances are also being conducted, according to the messages.

So far, no single cause has been identified, the messages state.

NEW FUNCTIONS CHECK:

Until a resolution is found, units are required to perform this additional function check on all M4A1 Product Improvement Program converted weapons, message 18-004 states.

PIP-converted weapons will be laser-etched with Xs over the burst setting.

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.

All M16 and M4 series rifles and carbines should have this additional function check performed within 10 days or prior to live fire, whichever comes first.

NEW IMMEDIATE ACTION DRILL:

TACOM has modified the traditional immediate action drill known as SPORTS to C-SPORTS, if the weapon does not fire when the trigger is pulled, message 18-005 states.

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.


-- Matthew Cox can be reached at matthew.cox@military.com.

This message has been edited. Last edited by: Sigmund,

I can see how that happened but it's really a non issue. Won't stop the Army from making it a stand down moment complete with it's own power point slide set.

Maybe I’m not clear on the differences between the M4 and M4A1; I thought the only significant difference was 3round burst vs. full auto. How would this affect the safety of the fire control group? Is this worn or out of spec parts? Or a booger hook issue?

The article clearly reported that the weapon fired when the firing selector was moved from one position to another. The trigger had been pulled without the gun’s firing prior to movement of the selector. It wasn’t a matter of someone pulling the trigger when he shouldn’t.

I would be very concerned if a gun didn’t fire when I pulled the trigger, but then did fire when I did anything else other than pulling the trigger, which is what happened in this report. A gun should fire when—and only when—the trigger is pulled; it would be like experiencing a failure to fire with a pistol and then having the gun discharge when I racked the slide to clear what I thought was a dud round.

I don’t know that I’ve ever tried to pull the trigger of an AR or M16 with the selector positioned between safe and fire (other than just now as a test), but if I had, I certainly wouldn’t want the gun to discharge when I moved the selector to fire.

Thanks for that informative article (as always).

^^^
“A sample of failed weapons is being disassembled, and a dimensional analysis is ongoing, officials said”

This to me is the most significant line in the report. It implies either worn parts (less likely) or out of spec tolerances(more likely).

quote:

Originally posted by gearhounds:
or out of spec tolerances(more likely).

Or even a bad design.

Just as the problem with the P320 discharging when it shouldn’t wasn’t discovered until someone did something that hadn’t been tried in formal testing, perhaps no one in the design process for the M4A1 trigger modification ever thought to see what would happen after the trigger was pulled with the selector positioned between two settings. If someone thought, “Why would anyone do that?” or never even considered the possibility, it wouldn’t have been tested.

quote:

Originally posted by gearhounds:
Maybe I’m not clear on the differences between the M4 and M4A1; I thought the only significant difference was 3round burst vs. full auto. How would this affect the safety of the fire control group? Is this worn or out of spec parts? Or a booger hook issue?

The three round burst fire control group has more parts, different parts, and AFAIK a different safety selector switch. It could be a bad part, the wrong part, or as someone else said no one tried this yet and now they know it can happen. I do know that if you keep your finger on the trigger while rotating the safety from semi to auto, the hammer will fall.

The question I have is whether he had the trigger held back while rotating the selector.

Bad parts are my guess. I've seen the failure demonstrated on video. With the selector partially betaeen "fire" and "auto," the trigger is squeezed and released. Something goes crunch in the fire control group. When the firer moves the selector to the "auto" position, the carbine discharges a single round without anything anywhere near the trigger.

All I know is I'm gonna try it next time I qual out of curiosity, I think we have all M4A1s now...

Very similar to the Rem 700 issue.

Well we still have Vietnam-era M16s. I will try it next chance I get.

It's out of tolerance parts. We had a few affected rifles in my arms room that will eventually get repaired.

quote:

Originally posted by Chowser:
Well we still have Vietnam-era M16s. I will try it next chance I get.

That would make the M16s at least 46 years old in 2018. Where did you come across this information? I assume by you stating "we" you mean the Army/DoD?

quote:

Originally posted by 229DAK:

quote:

Originally posted by Chowser:
Well we still have Vietnam-era M16s. I will try it next chance I get.

That would make the M16s at least 46 years old in 2018. Where did you come across this information? I assume by you stating "we" you mean the Army/DoD?

I mean, for me it was first hand - BCT in 2010 at Ft. Sill with M16A1's.

The article on TFB about this states the selector is being redesigned to snap into detent and not allow it to stay in between the stops. Interesting.

To address this the Army has reportedly made a change to the M4A1’s ambidextrous selector’s technical date package which will force the lever to snap into a fixed detent position rather than potentially floating between the safe, semi, full detent positions. It remains to be see if other branches have encountered similar issues. Regardless it looks likely that unit level armourers are set to be busy for the foreseeable future.

Link

quote:

Originally posted by xwesler:

quote:

Originally posted by 229DAK:

quote:

Originally posted by Chowser:
Well we still have Vietnam-era M16s. I will try it next chance I get.

That would make the M16s at least 46 years old in 2018. Where did you come across this information? I assume by you stating "we" you mean the Army/DoD?

I mean, for me it was first hand - BCT in 2010 at Ft. Sill with M16A1's.

Yes.that’s what we were told. We got them through the military loan program. 7 were beat to snot and I had to replace all the fcgs. Three were pristine and still in whatever that cosmoline stuff is. I never checked the serial numbers to actually determine when they were made. Anyone know where I can do that? It’d be nice to know how old they are. Or I can post the numbers here if someone can research them?

I realize completely different firearms, but that same set of actions (pulling trigger while safety in an in-between position) prompted the Ruger Mark IV .22lr recall.

Grabbed a newer rifle and checked. No issues.

This is one of the three that we got that were new old stock. Still wrapped and boxed.





This is one of our older ones. We got seven of these in first. These had failing fcgs (rifle would fire when trigger was released, some double fires, etc) and they had fcgs replaced with semi auto only versions. When I took over, I bought new full auto fcgs for them but haven’t bothered to install them.



I’m guessing they are late 60s / early 70s.

That issue of PS magazine brings back some memories. I can't quite read the setial number on the second rifle. Does it start with an 8 or a 3? Thanks.