The XM5 Rifle will replace the M4/M4A1 carbine within the close combat force, and the XM250 Automatic Rifle is the planned replacement for the M249 Squad Automatic Weapon
Both weapons provide significant capability improvements in accuracy, range and overall lethality. They are lightweight, fire more lethal ammunition, mitigate recoil, provide improved barrel performance, and include integrated muzzle sound and flash reduction.
Both weapons fire common 6.8 millimeter ammunition utilizing government provided projectiles and vendor-designed cartridges. The new ammunition includes multiple types of tactical and training rounds that increase accuracy and
are more lethal against emerging threats than both the 5.56mm and 7.62mm ammunition.
You say something about being under a rock?