22 LR Redline race gun red-dot optic combo developed ... One exception would be the modified polymer charging handle paired with the proprietary M4-22 black-nitride bolt assembly.
The British modified the M4 to replace the normal short-barreled 75 mm gun with the longer and more powerful 76 mm QF17-pounder cannon. The turret of the M4 was also modified so that the cannon ...