While early machine guns relied on recoil operations, modern assault rifles and light machine guns utilize gas operation. Gas operation is a bit more complex than recoil-based systems, as it ...

After Walther Arms entered the semi-automatic pistol market in the early 20th century, its designs quickly evolved. The Model 4 was one of the most popular pre-World War I pistols made. The ...

Within the iconic black sands of Iwo Jima (Figure 1) lies an environmental story that has remained untold—until now. New research reveals that the soil of this Pacific Island still harbors toxic ...