The M16A4 service rifle, donning the web sling, lies next to an M4 carbine rifle, donning the vigorous combat application sling, during annual rifle training at Puuloa Range Training Facility, March 23, 2015. All units are expected to transition from the web sling to either the VCAS sling, or the three-point sling by July 1. (U.S. Marine Corps photo by Lance Cpl. Adam O. Korolev/Released) - The M16A4 service rifle, donning the web sling, lies next to an M4 carbine rifle, donning the vigorous combat application sling, during annual rifle training at Puuloa Range Training Facility, March 23, 2015. All units are expected to transition from the web sling to either the VCAS sling, or the three-point sling by July 1. (U.S. Marine Corps photo by Lance Cpl. Adam O. Korolev/Released)