M4, FN Scar, HK416 & XM8
There are far more expensive weapons in the Pentagon's budget that carbine rifles, but none more important to tens of thousands of troops doing the fighting in Iraq and Afganistan.
For well over a decade, the military has relied on one company, Colt Defense of Hartford, Conn., to make M4 carbines that soldiers trust with their lives in combat. Now as Congress considers spending millions of more dollars on the guns, this exclusive arrangement is being sharply criticized as a bad deal for American forces and U.S. taxpayers.
Chek this link and explore the competing weapons and how they compare to the military's M4.