It is looking for a system that will perform better than the current issue rifle instead of looking for individual components. Furthremore it is being sought from commercial off-the-shelf parts.
Some of the noticable points are
- Free-float rail system with low-profile gas block in Coyote color
- Improved back-up sights
- Improved flash suppressor
- Improved charging handle - ambidextrous with extended latch
- Enhanced trigger - single stage, no slack, with consistent 4-5 lbs pull.
You can read the details from Soldier Systems Daily
http://soldiersystems.net/2015/03/14/us-army-working-on-m4a1plus-seeks-ndi-improvements-for-carbine/
From: Soldier Systems Daily
