Old story and long dead. Enlighten the guys spreading this rumor.
The "improved carbine" tests were terminated last summer. The Army looked at brand new factory tuned piston ARs for general issue and found that they weren't significantly more reliable than old DI M4s pulled out of inventory. Something like 99.5% vs. 99% so why spend the money.
My choice of rifle? The Army made the right decision.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek