m4 discharge semi auto safety check
courtesy stripes.com
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Oops. “The Army is updating procedures for use of the M4A1 automatic rifle after a soldier recorded cellphone video of his weapon firing when it shouldn’t have.”

The video, recorded in late March, shows the soldier operating a rifle that has been converted from a standard M4, which can fire a maximum three-round burst, to the fully automatic M4A1, according a safety message sent to troops on Tuesday.

Apparently about a thousand rifles have been found to fire after putting the safety selector between semi and giggle. Pulling the trigger does nothing, but then moving the switch to auto touches off a round.

Inspectors were able to replicate the malfunction depicted in the soldier’s video in about 10 percent of the weapons they checked, defense industry journal Soldier Systems reported.

Testing also revealed that carbines from a different manufacturer malfunctioned when switched from “safe” to “semi-automatic,” the journal reported.

None of the reports we’ve seen identify either manufacturer. The Army has issued procedures for checking individual rifles before using them in live fire situations.


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    • *Modified* M4s.

      M4s modified from 3-round burst to full-auto. Just moving the selector switch touches off a round…

      • I remember going through BCT in 05. One of the guys in our company had a freaking ANCIENT M16A2 (yeah we were still issued the A2 then) that had been armory refurbished and turned into an A2 (parts added in to make it burst capable and upper receiver with A2 sights and round handguards added). The drill sergeants all remarked that lucky for him we’d never use burst because his rifle would go full auto, then, like all great drill sergeants they proceeded to demonstrate said deficiency through about 4 magazines.

    • So they are pulling the trigger with the selector between SEMI and AUTO?

      Operator error? Even operators operating operationally are not perfect.

        • It doesn’t fire simply when moving the selector. It fires after an attempt to fire with the selector out of battery THEN moving the selector. The rifle will not fire without a trigger pull as stated in the headlines. The trigger needs to be pulled and then the selector moved. Try reading the article.

        • Yeah, this phenomenon is called ‘tricking’ or ‘staging,’ and can be done with many types of long-guns, mostly those striker-fired ‘single-action’ ones with ‘overhang’ triggers, particularly bolt-action ones.
          Even with a common bolt-action rifle, pulling the trigger with the safety ‘on’ to ‘test’ it can set up a ‘staging’ condition, where the trigger once pulled does not return to prop up the sear as it should; this leaves only the safety cam to hold the sear up in place against the striker tang. Since the trigger has been completely removed from the firing chain, if the safety is then released, it acts as the ‘trigger,’ and the gun fires.
          It sounds like these ‘not-really M4A1’s are doing something similar; By pulling the trigger with the selector between ‘semi’ and ‘auto,’ the rear disconnector is being taken out of engagement from the hammer, leaving only the ‘auto’ sear propping the hammer back. Moving the selector the rest of the way to ‘auto’ takes the ‘auto’ sear out of engagement, the trigger is no longer there to control the forward disconnector hook, and the hammer falls. It SHOULD only fire once, though, as the article mentions.
          An M4 with a burst-ratchet assembly puts another mechanism (ratchet wheel and pawl) between the disconnector and the ‘auto’ sear, and prevents the selector from becoming the ‘trigger.’
          I think. . .

          I don’t know if a ‘regular,’ unconverted M16A1 or A3 (full-auto) would do that, having never tried it.

        • I believe the auto sear is only in contact with the hammer when the bolt is out of battery so in this scenario I don’t think it’s a factor. To me it sounds like that the “in between position” has just enough clearance between the safety selector barrel and the trigger group to allow the hammer to come off the trigger sear and onto the disconnector but not enough to also disengage the disconnector. And then when moving to giggle position, the disconnector is cleared out of the way since the auto seer takes over timing duties from there.

          So its off the trigger sear but on the disconnector, the bolt is in battery so the auto sear isn’t catching, and the move to giggle pulls the disconnector away which is the only thing holding the hammer back at that point.

        • There is so much Total BS in the comments that I’m not going to even try to do individual replies.

          The very first piece of BS, of course, is the title on this post. None of the M4 with the defect were found to fire without pulling the trigger.

          They fire ONLY AFTER the operator pulls the trigger, the problem is that they don’t fire immediately after the operator pulls the trigger.

          The problem has been found in many of the latest batch M4 carbines from both Colt and FN (interestingly enough both prime contractors bought their fire control parts from the same subcontractor — so guess where the problem really comes from).

          The problem occurs when the operator first screws up by placing the selector BETWEEN the semi and full auto positions, if the operator then pulls the trigger with the safety selector set improperly the carbine fails to fire when the trigger is pulled, BUT it will then fire when the selector is moved to either the semi or full auto position.

          This malfunction would not be dangerous in the hands of properly trained troops, but then again if the troops were properly trained they would have never discovered the problem at all. The problem only occurs when the operator makes a mistake setting the selector and the problem is only dangerous if the operator then handles the weapon in an unsafe manner.

          With these carbines in the hands of well trained troops, this problem would rate nothing more than Mr Spock raising one eyebrow and saying “Interesting” — with these carbines in the hands of current US Army soldiers apparently it is a catastrophe – but it is still easy to verify and easy to fix (although fixing it requires replacing the fire control parts which is support level maintenance because neither soldiers nor unit armorers are authorized to disassemble the lower receiver).

          The real question is whether the specifications provided to the subcontractor were wrong or did the subcontractor ship faulty parts to both Colt and FN, if the contractor shipped faulty parts to both Colt and FN, then we have a situation where both prime contractors failed to check the parts that they received from the subcontractor.

      • Did you not read the words written on the page. He clearly said moving the safety selector made the weapon fire

    • okay supersoldier, if everyone was like you we wouldn’t need safeties at all would we?

      But stuff happens, so maybe a gun shouldn’t be able to be discharged without pulling the trigger.

    • And it’s monumentally stupid to have “carve-outs” for LE in laws that restrict full-auto weapons for citizens and civilians. Why the fuck would the police ever need full auto? Suppressing fire? Free-fire zones?

  1. The Matel Shooting Shell, a fail from its inception as far as I’m concerned. The only good thing I can say about the M16 and it’s ammo is they were light.

      • You probably said the M4 should start using Glock magazines as a joke, but you are half right. Most of
        the time when these rifles fail it is a feed issue. Feed issues are often traced back to faulty magazines. This is why we have no tilt or Magpul followers now. Polymer magazines seems to fair much better too. Polymer may split or crack over time, but at least it works it does not. The aluminum and stainless steel magazines both are prone to getting bent lips. I’m yet to have Glock magazine mess up. That and that little drum/box/rotary magazine of the Ruger 10-22, great designs.

  2. I know guys who spent their entire tour in Vietnam with the M16 on semi-auto.
    I guess the gun control crowd is right that these little black poodle killers have a mind of their own and it is never the little tide pod eater’s fault pulling the trigger.
    Have to ban those overcapacity magazines and assault features that turn the M-4 into a machine gun that fires thousands of rounds per second.

  3. The USMC infantry has the same problem with the M4s and M16s, one kids rifle was firing burst when it was set to semi. It comes down to these weapons being worn out and all of the military funding gets sucked up by the contractors. Line units don’t see diddly squat.

    I had a chipped lens in my RCO, many of the tritium tubes were broken, one of the corpsman held his M4 together with duct tape because the rear take-down pin would fall out. It takes almost an entire workup (6-7 months) to yellow tag something and get the replacement part for it.

  4. “Army Finds 10% of M4 Rifles Fire Without Pulling the Trigger” – When I was in the military, the saying was that “There’s always that 10% that doesn’t get the word.” Simplistically, that appears to be the case here.

  5. Waiting for Military Arms Channel to work up a snarky t-shirt declaring all military M4’s to be complete garbage.

  6. Direct Impingement has always been awful. The DOD brass and fat civie gun owners just refuse to become big boys and move on to gas piston. Ask any engineer , you can only do so many work around on a machine before it starts breakdown and there is no choice but to replace it.


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