U.S. SOCOM (Special Operations Command) has used its own, bureaucracy free, budget to design and manufacture special ammunition for the short barrel (10-15 inch) weapons (like the M-4 and SCAR Light). The new ammo, referred to as "5.56 Optimized", or "brown tip" (because the tips of the bullets are brown for easy identification) uses a bullet that is solid copper and 70 grains in weight (compared to 62 grains for the NATO standard 5.56 bullet). The solid copper design is believed to be based on a commercial design (the Barnes Triple-Shock X) that was introduced five years ago. The new round was designed to achieve better accuracy and hitting power at the ranges (under 300 meters) the short barrel weapons are most effective at. The brown tip ammo costs more, because of its unique design and small production runs, but SOCOM doesn't worry about that when it's for something that will make its operators more effective, and help keep them alive.