The resulting firearm designed around the Olin cartridges was the HK CAWS. With an outer casing of high impact plastic like HK's previous G11, the weapon was designed to reduce recoil through the use of an interior 'floating recoil system'. Despite the bullpup design, it was designed for ambidextrous use with ambidextrous fire selectors and safety levers and ejection converted from right to left by rotating the bolt head 180°. The chamber was configured to accept the proprietary belted cartridges as well as commercial 12ga rounds and the barrel could be fitted with a choke or choked barrel extension. The carry handle covers the cocking handle similar to the AR-10, and housed an optical sight which could be converted to a rail sight.