The 54-caliber barrel should be designated as XM297E1 and installed on the M109A6 test rig with the XM194 gun mount. The 56-caliber version with XM200 gun mount was redesignated as XM297E2 for the XM2001 Crusader. pic.twitter.com/oob3l5zFnC

— Ronkainen (@ronkainen7k15) October 23, 2023