An article I read suggested taking the best features of the M27 and applying that to the M4 and M16 - the biggest factor being better accuracy, better barrel life, and better performance at higher rate of fire. Most of this being due to the high quality cold hammer forged barrel with a free floating handguard. Retrofitting existing M4/M16 rifles with a barrel/handguard would be relatively cheap especially vs a new weapon system.
I don't even see much reason to leave the 5.56 NATO round. Maybe the 7.62 NATO change for something lighter/faster like the 6.5 calibers.
I don't even see much reason to leave the 5.56 NATO round. Maybe the 7.62 NATO change for something lighter/faster like the 6.5 calibers.