wound size and potential to incapacitate a person is greatly reduced. There have been numerous attempts to create an intermediate cartridge that addresses the complaints of 5.56 NATO's lack of stopping power along with lack of controllability seen in rifles firing 7.62 NATO in full auto. Some alternative cartridges like the 300 AAC Blackout (7.62×35mm) focus on penetration and stopping power at short ranges by sacrificing long-distance performance. These calibers are designed to be interoperable with the 5.56 by maintaining similar dimensions, which allows them to be used in a 5.56-chambered rifle with a simple barrel change. By late 2004, the 6.8mm Remington SPC (6.8×43mm) was in limited use with U.S. Special Operators. However, it was not adopted for widespread use due to resistance from officials on changing calibers. In 2007, both the U.S. SOCOM and the U.S. Marine Corps decided not to field weapons chambered in 6.8×43mm due to logistical and cost issues. In April 2022, the U.S. Army selected a new rifle and light machine gun as part of the Next Generation Squad Weapon Program. They will replace 5.56 mm weapons, being chambered in 6.8×51mm Fury that has greater accuracy and range while being more lethal than 5.56×45mm NATO and 7.62×51mm NATO against emerging threats. 5.56mm NATO versus .223 Remington The exterior dimensions of the 5.56mm NATO and .223 Remington cartridges are identical. While the cartridges are identical other than powder load, the chamber leade, i.e. the area where the rifling begins, is cut to a sharper angle on some .223 commercial chambers. Because of this, a cartridge loaded to generate 5.56mm pressures in a 5.56mm chamber may develop pressures that exceed SAAMI limits when fired from a short-leade .223 Remington chamber. As the chambers differ, the head space gauges used for the two chamberings differ. Brass case The dimensional specifications of 5.56 NATO and .223 commercial brass cases are identical. The cases tend to have similar case capacity when measured, with variations chiefly due to brand, not 5.56 vs .223 designation. The result of this is that there is no such thing as "5.56 brass" or ".223 brass", the differences in the cartridges lie in pressure ratings and in chamber leade length, not in the shape or thickness of the brass. In July 2012, the US Army made a request for vendors to supply alternative cartridge cases to reduce the weight of an M855A1 5.56 mm round