The shoot off will test the capabilities of the M4/M16 operating system against three other rifles: the Heckler and Koch-built HK416, the FNH USA-designed Mk16 SOCOM Combat Assault Rifle and the previously-shelved, H&K-manufactured XM8 carbine.My bet is that the HK416 gets the nod.
For one thing, it will probably be the least expensive choice. You can use existing lowers and just plop the new upper on top. For another, you won't have to retrain your entire military to use a new weapon system; again, very cost efficient. But then, on the other hand, when has that ever made a difference???