Russo-Ukrainian War: The M240 240mm Heavy Mortar

Source: Reddit

     A soldier of the 3rd. Assault Brigade poses next to one of the unit's handful of colossal M240 240mm heavy mortars. The M240 mortars in use by Ukraine had been in storage until an unknown number were withdrawn, refurbished, and put back into service. Today, the M240 is the largest mortar in operational service in the world. Sometimes classified as a siege mortar, the M240 is designed to bombard fortified positions and the initial design commenced in 1944, being a scaled up version of the PM-43 160mm heavy mortar. Prototypes of the M240 were tested into 1950 and once accepted for service, production started in 1951 with units receiving the M240 commencing in 1953. In total, 329 examples of the M240 were built when production ended in 1958.

     With a combat weight of 4.6 tons and a barrel length alone of 17.6 feet, the M240 requires a maximum crew of 11 to operate effectively. A tow vehicle (usually a MT-LB tracked prime mover or a Ural 373 series 6x6 truck) moves the M240 about as well as carries the crew. Between one to two additional vehicles normally accompany the mortar with one containing ammunition while the other carries equipment and apparatus to assist in emplacing the M240 into a chosen firing position. The maximum tow speed is 25 miles per hour.

     The barrel is of the smooth-bore type and uses a breech-block. The 2-wheel carriage permits a total traverse of 18 degrees and the barrel can be elevated to a minimum of 45 degrees to a maximum of 65 degrees. Both traverse and elevation is manually controlled using gears situated on the left side of the barrel. Sighting is done using older MP-46 or MP-46M panoramic sights or by using a K-1 collimator sight. The carriage is equipped with a recoil assembly, used to reduce firing vibration and be the bridge between the barrel and the mount.

     Loading the M240 is no simple process. As the mortar is a breech loader and cannot be loaded while the barrel is elevated, the barrel is brought down to a horizontal position. The standard 3OF-864 HE (High-Explosive) bomb has a total weight of 290 pounds of which 75 pounds accounts for the explosive in the bomb's warhead. The bomb is brought to the M240 using a 2-wheeled trolley and once near the breech, long-handled tongs are used to pick up the bomb with two men on either side of the projectile providing the lift. A fifth man stands behind the bomb, making sure the bomb's fins are steady and not damaged. Once the bomb is pushed into the barrel, the breech is closed and the M240's barrel returned to battery. A well trained crew can manage a rate of fire of 1 round per minute.

     The M240 is capable of lobbing the 3OF-864 bomb out to a maximum range of 6 miles. A RAP (Rocket Assisted Projectile) version of the 3OF-864 (designated the 3F2 Gagara), fitted with 3M15 rocket motors, can extend that range out to 12 miles. However, even with the RAP bomb, the M240 is within counterbattery range of guns such as the 122mm D-30 howitzer, BM-21 Grad MLRS (Multiple Launch Rocket System), and drones such as the ZALA Lancet loitering munition as well as other FPV drones. Bringing the M240 into action takes up to 25 minutes from the halt and with apparatus to assist with the set up. The M240 can only fire from firm ground and if the ground is too hard, explosive charges are used to blow a pit into the ground for the base plate to settle into. While preparing to fire may go unnoticed, after the first bomb is fired, detection may only be a matter of time. It takes up to 15 minutes to return the M240 to traveling condition and this makes “shoot and scoot” tactics of very limited value. This issue is the main reason the Soviet Union developed the 2S4 Tyulpan (“Tulip”) which is a tracked, self-propelled mounting of the 240mm 2B8 mortar (a modified M240) that entered service starting in 1975.

     Other than the common 3OF-864 ammunition, it is believed the Ukrainians also have some stockpiles of the 3F2 Gagara bombs and a more limited availability of the 1K113 Smelchak (“Daredevil”) semi-active, laser-guided mortar bomb. The latter is composed of a 3F5 240mm HE projectile, a optoelectronic correction head, four adjustable fins, and six solid-fuel rocket motors. In order to effectively utilize the 3F5 bomb, it requires soldiers on the ground equipped with either a 1D15 or 1D20 laser rangefinder/designator. The 1D15 has a maximum range of 3 miles while the 1D20 has a 4 mile maximum range. The 1K113 itself has a maximum range of 5.7 miles.

     Doctrine in using the 1K113 as designed involves aiming the M240 towards the designated target and firing a standard round. The observation team, already in place (and usually no more than 5 miles from the target), reports the impact and calls back adjustments to the firing unit. After the gunner makes the corrections, the 1K113 is then loaded and fired. The soldier manning the 1D15 or 1D20 unit aims the designator at the target where it receives a radio signal from the M240 firing position regarding the bomb's trajectory. As the bomb nears the target, the designator switches to targeting mode, “painting” the target with laser pulses which the bomb's correction head picks up via reflection. Around .5 of a mile from impact, the rocket motors are utilized to make any corrections to the flight path to ensure successful impact. The usual deviation from the aim point is no more than 1.8 meters.

     As of July 28, 2025, the Russians have lost a total of sixty-one 2S4 Tyulpan (10% of the total production run) while the Ukrainians have not lost any of their M240 towed mortars.

M102 105mm Howitzer: Battle for Quảng Trị

Source: The Associated Press

     On March 30, 1972, the Chiến dịch Xuân Hè 1972 (1972 Spring - Summer Offensive), better known as the Easter Offensive, was launched by the People's Army of Vietnam (PAVN) supported by Việt Cộng forces. In the attack, the PAVN took the city of Quảng Trị as well as Quảng Trị Province along with a portion of Thừa Thiên Province. The Army of the Republic of Vietnam (ARVN), while initially thrown back, dug in along the My Chanh River north of Huế and halted the PAVN advance with the assistance of U.S. air support. On June 14, 1972, I Corps commander Lieutenant-General Ngô Quang Trưởng commenced planning to retake Quảng Trị Province with a combined U.S. and ARVN mission called Operation Lam Son 72.

     On June 27, 1972, the U.S. 9th. Marine Amphibious Brigade launched a feint assault along the Cua Việt River but on the ground, RVN Marine and RVN Airborne forces met stiff resistance from PAVN troops as they moved northwest of the Thạch Hãn River. To assist, on June 28, U.S. Marine Medium Helicopter Squadron 164 (HMM-164; the “Death Riders”) and HMM-165 (the “White Knights”) airlifted the 1st. and 4th. RVN Marine Battalions behind PAVN positions. After further fighting, both the Marine and Airborne forces reached the outskirts of Quảng Trị on July 7. The defenders within the city were not the cream of the PAVN crop and instead, were relatively untrained replacement soldiers and militiamen. This was because the PAVN 304th. Division and 308th. Division had pulled their more experienced fighters out of Quảng Trị to protect them from U.S. air power. Despite this, PAVN forces in the city had artillery support, terrain advantage, and had well prepared positions to the point that ARVN attacks against the city met with stiff resistance. On July 11, U.S. Air Force Boeing B-52 bombers bombarded the city and in an effort to cut off the PAVN supply line, HMM-164 and HMM-165 were again called in to drop the RVN 1st. Marine Division north of the city. It was costly as three helicopters were downed with another 25 receiving various amounts of damage from viscous anti-aircraft fire. After three days of brutal combat against the PAVN 48th. Regiment of the 320th. Division (the Đồng Bằng Division or Delta Division), the regiment was forced to retreat. By July 20, the Marines had consolidated their positions while the RVN Airborne forces continued to penetrate into Quảng Trị. Two days later, the 5th. Marine Battalion was airlifted by HMM-164 to interdict PAVN supply lines near the Cua Việt River and combined with two additional Marine battalions, including tanks, managed to defeat PAVN forces in the area after two days of fighting. By July 27, it was the RVN Marines assaulting the city after relieving the diminished RVN Airborne troops and for weeks, combat raged in bitter house-to-house fighting. On September 9, 1972, the 147th. Marine Brigade and the 258th. Marine Brigade pushed on the heavily defended city center which finally fell on September 15. The brutal combat cost ARVN forces 3,658 dead with 20 U.S. servicemen killed while it is estimated PAVN losses were at least 10,000 killed. In support of the RVN troops, the U.S. Air Force and U.S. Navy (flying from five aircraft carriers) flew 5,461 close air support sorties while the U.S. Air Force launched 2,054 B-52 bomber sorties.

     The Associated Press photograph shown here was taken on July 10, 1972 and shows a RVN Airborne artilleryman manning a U.S. built M102 105mm howitzer. The location was a firebase situated near La Vang which was 3 miles south of Quảng Trị. The M102 was a lightweight (1.5 tons) howitzer whose design commenced in 1962 with the first examples entering service in 1966 to replace the World War Two era M101A1 howitzers. The gun used a box trail that had a platform beneath the gun that when in place and the wheels raised, allowed the gun to be traversed a full 360 degrees. Gun depression was a maximum of 5 degrees with a maximum elevation of 75 degrees. Recoil was via a hydro-pneumatic system and the gun used a vertical sliding-wedge breech. The standard high-explosive shell weighed 33lbs. and with the maximum powder charge, the range was 7.1 miles. With a rocket-assisted shell, the range was increased to 9.4 miles. Today, the M102 is no longer used by the U.S. Army, having been replaced by the M119 though it still exists in some U.S. National Guard inventories. It is also still used by the U.S. Marine Corps but usually only for ceremonial duties. The U.S. Air Force continues to use the M102 in the Lockheed AC-130J Ghostrider gunship. Outside of the U.S., a handful of operators still use the M102 with the largest user being Jordan that maintains 50 guns on inventory.