The XM7, previously known as the XM5, is the U.S. Army variant of the SIG MCX Spear, a 6.8×51mm (.277 in), gas-operated, magazine-fed, assault rifle[1][6] designed by SIG Sauer for the Next Generation Squad Weapon Program in 2022 to replace the M4 carbine. The XM7 features a free-floating reinforced M-LOK handguard for direct accessory attachment onto the "negative space" (hollow slot) mounting points.