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Potential safety issue with M4/M4A1

Posted: Mon Dec 24, 2018 5:57 pm
by ghostrider
I thought I saw one report that said the issue could affect AR-15s as well:

https://armyreservemarksman.info/2018/0 ... ge-m16-m4/

https://taskandpurpose.com/army-fix-glitch-m4-carbines/

Re: Potential safety issue with M4/M4A1

Posted: Wed Dec 26, 2018 4:14 pm
by The Annoyed Man
I sent the author an email asking if this was a concern or not for owners of semiauto AR15s. Here’s the answer I got:
This problem is due to a "stack up" of differing tolerances from different parts. While it could potentially be an issue in any AR-15 build comprised of parts from different makers it's only been identified in issue arms.

Adding this check to the function check is prudent and takes seconds to accomplish.
So.... the next time I’m at that end of my house, I’ll get them all out and check.

Re: Potential safety issue with M4/M4A1

Posted: Wed Dec 26, 2018 7:31 pm
by Paladin
Can't say for sure, but it looks like this is an issue with BURST or AUTO weapons:
...Move the selector lever to the SEMI position then move the selector to a position between SEMI and AUTO (BURST for non M4A1’s) and squeeze the trigger. The hammer should drop when trigger is squeezed. If the hammer drops, repeat by slightly repositioning selector between SEMI and AUTO (or BURST). If the hammer does not drop when the trigger is squeezed, this is a failure. Record this information and continue to the next step.

Re: Potential safety issue with M4/M4A1

Posted: Thu Dec 27, 2018 6:37 pm
by ninjabread
ghostrider wrote:
Mon Dec 24, 2018 5:57 pm
I thought I saw one report that said the issue could affect AR-15s as well:

https://armyreservemarksman.info/2018/0 ... ge-m16-m4/

https://taskandpurpose.com/army-fix-glitch-m4-carbines/
All of mine failed the test on step 3.
Move the selector lever to the SEMI position then move the selector to a position between SEMI and AUTO (BURST for non M4A1’s)