"Interim" presumably meaning this is a gap-filler until something better comes along?:
Desired Attributes of Interim Combat Service Rifle:
• The rifle must be a Commercial Off The Shelf (COTS) system readily available for purchase today. Modified or customized systems are not being considered.
• Caliber: 7.62x51mm
• Available barrel lengths, to include 16 and 20 inch barrels, without muzzle device attached.
• Muzzle device capable of or adaptable to auxiliary devices for:
** -- Compensation of muzzle climb
** -- Flash suppression
** -- Sound Suppression
• Fire Control: Safe, Semi-automatic, and fully automatic capable.
• All controls (e.g. selector, charging handle) are ambidextrous and operable by left and right handed users
• Capable of mounting a 1.25 inch wide military sling
• Capable of accepting or mounting the following accessories.
** -- Forward grip/bi-pod for the weapon
** -- variable power optic
• Detachable magazine with a minimum capacity of 20 rounds
• Folding or collapsing buttstock adjustable to change the overall length of the weapon
• Foldable backup iron sights calibrated/adjustable to a maximum of 600 meters range
• Weight less than 12lb unloaded and without optic
• Extended Forward Rail
https://www.fbo.gov/index?s=opportun...=core&_cview=1
Desired Attributes of Interim Combat Service Rifle:
• The rifle must be a Commercial Off The Shelf (COTS) system readily available for purchase today. Modified or customized systems are not being considered.
• Caliber: 7.62x51mm
• Available barrel lengths, to include 16 and 20 inch barrels, without muzzle device attached.
• Muzzle device capable of or adaptable to auxiliary devices for:
** -- Compensation of muzzle climb
** -- Flash suppression
** -- Sound Suppression
• Fire Control: Safe, Semi-automatic, and fully automatic capable.
• All controls (e.g. selector, charging handle) are ambidextrous and operable by left and right handed users
• Capable of mounting a 1.25 inch wide military sling
• Capable of accepting or mounting the following accessories.
** -- Forward grip/bi-pod for the weapon
** -- variable power optic
• Detachable magazine with a minimum capacity of 20 rounds
• Folding or collapsing buttstock adjustable to change the overall length of the weapon
• Foldable backup iron sights calibrated/adjustable to a maximum of 600 meters range
• Weight less than 12lb unloaded and without optic
• Extended Forward Rail
https://www.fbo.gov/index?s=opportun...=core&_cview=1