The U.S. Army Must Replace the Old M4 Carbine. What Would Make the Ultimate Rifle?

The U.S. Army is looking for a new weapon for infantry troops. After a half century of using the M16/M4 carbine series of weapons, the Army is looking for a weapon with increased range and lethality to deal with future threats. Although the search is still in its early stages, looking at the threats and the current state of small arms technology we can get an idea of what the service might shoot for--figuratively speaking--in a new soldier weapon. 

The current U.S. Army weapon that the service eventually seeks to replace is the M4 carbine. An evolution of the original M16 introduced in the mid Sixties, the M4 is more compact and more reliable than its ancestor. Thanks to improved ammunition the M4 is able to penetrate lightweight body armor, and the use of optics allows soldiers to place rounds on target more accurately at longer ranges than ever before. 

All of that having been said, the M4’s basic design precludes important upgrades. The use of a direct impingement operating system, although simple and effective, requires more frequent cleaning and alternatives exist. The 5.56-millimeter round, although lightweight and logistically appealing, is reaching a dead end performance-wise and a good argument exists that it needs replacing.