http://www.thefirearmblog.com/blog/2018 ... ischarges/
A potentially fatal flaw with some of the US Army’s M4A1’s has recently emerged. Unofficial footage, filmed by troops, surfaced showing a serious malfunction where an M4A1 carbine unintentionally discharged as its selector was shifted from semi to full auto. At least 900 carbines are known to be affected by the flaw.
The first problems were discovered by troops at Fort Knox, Kentucky in March with one solider finding that his carbine discharged as he rotated the selector fully into the detent full auto position. Since that incident a similar problem has been noted with weapons made by another manufacturer, with the weapon firing as the selector was pushed from safe to semi. This means both Colt and FN production guns have been impacted.
The Army’s Tank and Automotive Command (TACOM), which is responsible for small arms maintenance, issued two separate safety directives in March and April – the second of these noted that the malfunction “is now believed to go beyond just the M4A1 PIP [product improvement program] weapons.” This means other rifles including M4s and M16A2, A3 and A4s may also suffer from the defect. The second safety message stated that 881 M4A1s had been tested and had exhibited the malfunction.
One potential explanation might be that the new ambidextrous safety/selector levers used in the Army’s M4A1 Product Improvement Program package might be out of spec.
