MK11 Mod 0 vs xm110

[woo18]

I know Knight's Armament is the manufacturer of both of those rifles(MK11 Mod 0 and xm110), what is the main difference between the two? I remember reading that they had to make some modifications to the MK11 Mod 0 in order to meet the requirements for the XM110 competition. What were those modifications?

 

[Bartholomew Roberts]

The XM110 has a dimpled barrel to reduce the weight to meet Army requirements while retaining some of the stiffness and accuracy of a heavy barrel. The XM110 has a different rail system (the URX II vs. the Free-Floating RAS of some Mk11s). IIRC, the XM110 is also a flat dark earth finish instead of black.

You can find more info here:
http://www.ar15.com/lite/topic.html?b=3&f=12&t=228443