It’s smaller, lighter and better suited for modern battles. And it might be headed into the hands of U.S. Marines. Marine Corps officials wrapped up testing two new rifles as a possible replacement to the M-16A2 in stock now: the short M-4 carbine and the M-16A4, an upgraded model of the rifle Marines use now. The jury’s still out, but a decision is expected soon. So far, though, the M-4 is garnering praise from the Marines and looks to be a front-runner. However, some soldiers who fought in Afghanistan have expressed concerns about the M-4, which also is standard issue...