This is an “Interim” rifle, not a long term solution. The long term plan is to swap out the 5.56 round for one in the 6.5 to 7mm range. Lower recoil, much better ballistically, and still with plenty of punch. Something along the lines of the 6.8 SPC necked to 6.5 mm would be ideal. 2,700-3,000 FPS with a 100-130 grain 6.5 bullet would certainly work!
The 6.5 to 7mm diameter was identified as the optimum as long ago as before WW II. It’ll be good to see it finally adopted, as it should have been 70 years ago.
http://www.thedrive.com/the-war-zone/10147/the-army-is-once-again-looking-to-replace-the-5-56mm-cartridge
http://www.dtic.mil/get-tr-doc/pdf?AD=ADA512331
Oops, my bad. It’s .264 USA. https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.thefirearmblog.com/blog/2014/11/10/usamu-264-usa/amp/&ved=0ahUKEwiJk7TZhcjVAhUBHGMKHe5WDQIQFgglMAA&usg=AFQjCNGBkwFAj9eDJlJarqolrcsTV-VIzw&cf=1