several North Korean provocations. During the 2022 Russian invasion of Ukraine, Ukraine used M109 howitzers which were donated by Western countries. Design The M109 was developed by the Ground System Division of United Defense LP, now BAE Systems Land and Armaments. Armament Primary by Watervliet Arsenal: M126 Cannon (or M126A1) 155 mm Howitzer (M109), M185 Cannon 155 mm Howitzer (A1/A2/A3/A4), or M284 Cannon 155 mm Howitzer (A5/A6) Secondary: .50 caliber (12.7 mm) M2 machine gun, Mk 19 Mod 3 40 mm Automatic Grenade Launcher, 7.62 mm M60, M240 machine gun or L4 machine gun Hypervelocity Projectile (HVP) In January 2016, the U.S. Army test-fired hypervelocity projectiles originally designed for use by U.S. Navy electromagnetic railguns. They found that they significantly increased the gun's range. The Army is looking into using the M109 Paladin firing the HVP for ballistic missile defense, as traditional missile interceptors are expensive, and gun-based missile defense used for point defense would use artillery at a much lower cost per round. The HVP is capable of being fired out to from a conventional cannon. It weighs with a flight body containing its guidance and warhead—less powerful, but more agile to hit small, high-speed targets. Modifications will be needed for the Paladin to effectively shoot the HVP, possibly including different propellant to achieve higher velocities, automated reloading systems to fire quickly enough to defeat salvo launches, improved barrel life, and a new fire control and sensor system. During a test of the Air Force's Advanced Battle Management System (ABMS) in September 2020, an HVP fired from an Army Paladin howitzer successfully intercepted a BQM-167 target drone simulating a cruise missile. Variants M109 First produced in 1963. It had a 155 mm M126 Cannon in an M127 Mount, and carried 28 rounds of 155 mm ammunition. It was also armed with a .50cal M2HB machine gun with 500 rounds of ammunition. Easily identified by its short barrel and a double baffle muzzle brake with a large fume extractor just behind it. Maximum range of 14,600 meters. M109A1 Replaced the M126 Cannon with a 39 caliber M185 Cannon, featuring a longer barrel while increasing maximum range to 18,100 meters. M109A2 Incorporated 27 Reliability, Availability, and Maintainability (RAM) mid-life improvements. Most notably, the long barreled 155 mm M185 Cannon in the new M178 gun mount, ballistic protection for the panoramic telescope, counterbalanced travel lock, and the ability to mount the M140