The smoothbore, muzzle-loading M252 medium weight mortar system offers up accurate long-range indirect fire support to American ground forces. It is an 81mm high-angle-of-fire system that is crew-served, entering US Army service in 1987. The American M252 is based on the standard British L16 81mm mortar.
 |
| The M252, 81mm mortar replaced the aging M29 series of 81mm mortars in service with the US Army and USMC. |
The M252 consists of several key components making up the whole. These include the M253 Cannon (firing tube), the M177 Mortar Mount, the M3A1 Baseplate and the M64A1 Sight Unit. The M253 Cannon is 50 inches long and accepts a variety of munitions type for fire including high-explosive (HE), red phosphorous and smoke, illumination and other NATO-accepted rounds. The barrel is capped with the Blast Attenuation Device (BAD) for crew protection. Elevation is accomplished through the use of a screw-type elevation and traverse system. A crew of three is recommended for maximum firing efficiency.
The M252 has capable ranges of 83 meters minimum and 5,935 meters maximum. The entire unit weighs 91lbs. A maximum rate-of-fire of 30 rounds-per-minute is attainable for up to 2 minutes. Sustained firing falls between eight and sixteen rounds-per-minute. The M252 replaced the aged M29 81mm mortar and is in service with the United States Army and United States Marine Corps.
5-cm leichte Granatwerfer 36
The 5-cm Granatwerfer 36 (abbreviated as "leGrW 36") was the standard light mortar utilized by the German Army in the early years of World War 2. Engineers tried to complete a useful portable 50mm system that could benefit squad-level operations but instead created an overly complex and heavy system with limited range - proving to be a detriment to a resource-strapped Germany by the middle and end years of the war. In the end, the leGrW 36 led a limited existence and was ultimately passed down to second-line units as more favorable weapons replaced. The leGrW 36 was utilized by Nazi Germany, Bulgaria and Slovakia.
 |
| Though heavy for a light mortar, the leGrW 36 could be carried by a single soldier, his ammunition supply following behind. |
Germany held something of an advantage during the inter-war years following World War 1. While other national armies were being downsized and the world, as a whole, was war-weary, thoughts of rearmament played through the heads of German authorities. The standing German Army had essentially been dismantled down to the rivet following the cessation of hostilities but the rise of a new Germany meant that the nation held little reservation in resurrecting a new modern army from scratch. Attempts by the Free World to curtail such growth eventually fell to naught, for Hitler and his underlings were quick to bypass any international restrictions at their leisure, assuring a Second World War was at hand. As such, general thinking in terms of weapons development during this time often combined necessity with novel concepts, often times producing sophisticated and complex systems beyond the scope of a wartime economy.
 |
| With rearmament there came the need for a light 50mm infantry mortar system to compliment squad actions. The German firm of Rheinmetall-Borsig AG went about designing their new leGrW 36 (leichte Granatwerfer 36) along a different set of ideas beginning in 1934. |
The launch tube would be fixed to the baseplate while trajectory support would come from a simple monopod-type assembly. In contrast, most mortar systems utilized a separate baseplate attached to the firing tube with an accompanying bipod assembly for support. A collection of traverse controls were integrated into the baseplate itself and an telescopic sight was added to promote accuracy at range. The leGrW 36 was also made somewhat portable by a single infantryman thanks to an integrated handle though the overall weight of the little system left something to be desired (just over 30lbs). The firing action was accomplished through use of a trigger as opposed to an impact firing pin common in other light mortar designs. The leGrW 36 had the added benefit of being made ready to fire almost immediately thanks to its design - the operator need only set the system down, adjust traverse and elevation and introduce a 1.98lb projectile into the firing tube. Interestingly, the leGrW 36 was designed to fire only HE (High-Explosive) projectiles and nothing more. Conversely, most other mortar-type weapons made use of smoke, illumination and incendiary rounds to make the most of such a frontline weapon. The projectile itself was of a teardrop shape with a tapered base, adorned by eight smallish stabilization fins.
The weapon fired a TNT-filled 50mm projectile at a muzzle velocity of 246 feet-per-second within a minimum range of 55 yards and out to a maximum range of 558 yards. The operator could adjust the trajectory of the mortar from 42- to 90-degrees with traverse as well. A trained crew of two could fire off between 15 and 25 projectiles per minute.
The LeGrW 36 officially entered service with the German Army in 1936 and was fielded up until 1945 despite production being abandoned in favor of cheaper and more capable systems in 1941. In practice, the nifty little weapon proved too complicated for the utilitarian task at hand. The German soldier generally found operation of this weapon too complicated in the heat of battle and the overall weight worked against it when transporting the system under fire, both offsetting any potential benefits. The projectile itself was found to be too "light" to be effective in the intended role. Additionally, where the mortar carrier went, his ammunition carrier needed to follow and this weight of ammunition came at a price all its own. To help compound issues, the range of the leGrW 36 was quite restricted when compared to her contemporaries, meaning that the novel telescopic sight was all but useless for a simple line drawn about the barrel itself proved enough to assist the operator in aiming the weapon. A such, the telescopic sight was dropped from production by 1938. The leGrW 36 also relied upon complex construction utilizing valuable materials, making it a dispensable item when it came time for Germany to cut back on the overly complicated and expensive war equipment plaguing her efforts. The limitations often times sent German soldiers clamoring for captured Soviet and French 50mm systems, preferring those of the former to that of the latter in most cases.
As such, the leGrW 36 led a relatively short operational life. She was gradually removed from frontline service and those numbers already in circulation were passed down to second-line units, defensive units and some Italian forces in need of ranged firepower. Some leGrW 36s were known to be in defensive action along Hitler's "Atlantic Wall" to the West.
M224, 60mm Mortar
The M224 is the current portable mortar system in service with the United States Army and Marine Corps. The system provides a high-angle attack weapon that can be used in close proximity to friendly troops. Its indirect fire support and relative light weight handling characteristics has proven effective in support of ground forces, special operations units and mountain elements as well as airborne forces alike. The M224 was selected as a replacement for the M2 and M19 series of 60mm mortars which were in operational use since the days of World War 2. The M224 supersedes these aged designs in providing for an overall improved effective range.
 |
| The M224 replaced the World War 2-era M2 and M19 mortars in service with US ground forces. |
The M224 can be broken down into its core components consisting of the base plate, sighting unit, bipod and firing tube (also cannon or barrel) altogether weighing in at 46.5lbs. The baseplate comes in two flavors designated as the M7 and the M8. The M7 is utilized for conventional firing and attaches to the base of the firing tube while the M8 offers up a hand-held firing option. The M7 baseplate features a screw-type elevation and traverse mechanism for changing the angle of fire. Sighting is accomplished through the M64A1 Sight Unit which is attached to the bipod mount via a conventional dovetail arrangement. The bipod is designated as the M170 and fits to the forward end of the firing tube. The 40-inch long barrel is officially designated as the M25 Cannon and is of a smooth bore, muzzle-loading design which also includes the firing mechanism, base cap and an additional short-range sight at the base. The weapon system also features a spring-type shock absorber to dampen recoil.
A crew of three is recommended for maximum operational efficiency. Effective maximum ranges vary depending on the chosen method of fire (conventional or hand-held). For conventional fire, the range of the M224 is listed at 3,490 meters (approximately 2.17 miles) while a range of 1,340 meters is approximated for hand-held firing. Weights vary dramatically as well, again, depending on selected method of fire. The unit weight for conventional firing is 48lbs while the hand-held firing weight is listed at just 18lbs. A maximum rate-of-fire of 30 rounds-per-minute can be attained for up to four minutes with a sustained rate-of-fire of 20 rounds-per-minute for up to twenty minutes.
The M224 is cleared to fire variety of ammunition types including standard practice and training rounds, infrared and standard illumination rounds, white phosphorous smoke projectiles and high-explosive (HE) munitions with multi-option/point detonation fuses. A single M224 unit cost is listed as $10,658.
8-cm schwere Granatwerfer 34
The 8-cm Granatwerfer 34 (GrW 34) - Heavy Grenade-Launcher Model 1934 - was a German Army favorite throughout the whole course of World War 2. Despite the official designation classification, she was often classified as a medium mortar and was produced from 1934 into 1945. The system performed highly-effectively (particularly in the hands of a trained mortar team) and was respected by Allied troops for her excellent rate-of-fire and high accuracy at distance. The weapon proved so critical to German Army operations that it was fielded wherever her troops were fighting. Her production in number and her general battlefield usefulness ensured her place in World War 2 lore.
 |
| The 8-cm Granatwerfer 34 became the standard German medium mortar beginning in 1934 and saw production and use into 1945. |
Rheinmetall-Borsig AG was charged with the design and development of this mortar system. The protracted design period lasted from 1922 to 1933, a period which saw German rearmament in spite of the restrictive powers of the Treaty of Versailles following World War 1. The mortar system was nothing more than a revision of the influential French Brandt mle 27/31 81.4mm system of 1927, this time with a German branding. Crews were trained in her basic functions but soon - moreso through operational experience - developed speedy response times in her deployment, aiming and firing - making themselves one of the more feared adversaries of the war. German mortar crews represented some of the finest masters of their craft in the entire conflict. To keep up with demand, several manufacturing firms were enlisted to lend a hand in wartime production of the GrW 34 while still more were used for production of the all-important projectiles needed to make the GrW 34 a successful weapon system.
 |
| Despite her dedicated pages in World War history, the GrW 34 was anything but a unique and wholly special design, passing on much of the kudos to her excellently trained crews. Her design was highly conventional for its time - her arrangement consisted of nothing more than the standard base plate, a bipod (with aiming optics and handwheels) connected to the firing tube and the firing tube itself. |
The system could break down into these three major components for ease of travel. The firing tube itself was of a smoothbore internal design. Two barrel types existed in a steel and alloy form, differentiated by the systems overall weight gains as 136.6lbs and 125.6lbs respectively. Barrel length measured in at 45 inches (1,143MM). The base projectiles were 7.71lbs in weight and activated via percussion fuses. Range could be slightly extended through use of additional powder charges. The base plate was rectangular in shape and fitted to the bottom of the firing tube. There was a rounded handle for carrying the individual component from location to location. The bipod fitted most of the critical aiming functions of the GrW 34. There was a traversing handwheel as well as a cross-leveling handwheel for general aiming while a panoramic sight afforded for finer adjustments against a target area. Elevation fell within a range of 45- to 90-degrees while traversing was limited from 10- to 23-degrees. Muzzle velocity was listed at 571 feet per second and the weapon was ranged out to 2,624 yards (2,400 meters).
The GrW 34 was cleared to fire the conventional High-Explosive (HE) and smoke projectiles but her true arsenal was more expansive. She could fire illuminating rounds for night-time work as well as any captured enemy ammunition fitting her caliber (at the loss of some performance however). There was an interesting bouncing projectile known by the designation of "8-cm Wurfgranate 39" that utilized a tiny rocket motor to "bounce" itself off of the ground of a target area, exploding in mid-air and spewing her dangerous fragmentation payload about the surrounding area. These, however, proved too costly to produce in any number and were therefore something of a rarity.
The basic pear-shaped projectiles (stabilized by multiple small fins at the rear of each shell) were dropped from the muzzle-end of the firing tube straight down the awaiting barrel. They then struck the awaiting firing pin at the base of the firing tube, subsequently igniting the propellant charge and sending the projectile on its flight trajectory based on the predetermined path through careful aiming. A trained crew of three could let off between 15- to 25-rounds per minute. One crewmember managed the ammunition supply while another fine-tuned the aiming adjustments. The third crewmember served as an assistant and could also stabilize the bipod by hand when the system was fired for even more steadiness. All three helped to transport the three components of the GrW 34 system.
The base Granatwerfer 34 was spawned into a few published variants. These included the Granatwerfer 34/1, a modified Granatwerfer 34 for use on self-propelled vehicles such as the SdKfz 250/7 series halftrack, and the kurzer 8-cm Granatwerfer 42 (or "Stummelwerfer"), essentially a lightened form of the base model (with half the range) sporting a shortened barrel system for use by airborne personnel. The Stummelwerfer saw service beginning in 1942 but was rarely in use with her intended airborne forces. Instead, the system went on to replace the complex and expensive 5-cm lwGrW 36 light mortar series keeping all of her GrW 34 benefits minus the excellent range.
Other than the German Army, the other key operator of the Granatwerfer 34 system was ally Bulgaria.
M29, 81mm Mortar
The American M1 81mm Mortar, like the upcoming M2 60mm Mortar, was based on a French design by Edgar William Brandt (1880-1960). The M1 was a derivative of the French mle 27/31 system (itself an improved form of the Stokes Trench Mortar of World War 1 fame) and slightly altered to suit American needs. The M1 became the standard American battalion mortar of World War 2 and saw action in the Korean War as well as the Vietnam War until it was eventually replaced by the M29 - a lighter 81mm system with a longer reach.
 |
| The Mortar, 81mm M1, was another French-inspired weapon that went on to see successful combat actions with American forces in World War 2, Korea and Vietnam. |
As a weapons engineer, Frenchman Brandt was responsible for a slew of advancements in the field of mortars and projectiles that led to the development of varying 60mm, 81mm and 120mm systems while at the same time furthering HEAT rifle grenade and HEAT-warhead anti-tank weaponry technology. Brandt's designs were heavily copied throughout World War 2 and beyond, making them commonplace throughout the globe in the years following.
 |
| The US Army had already garnered experience in the use of the 3" Mk I Stokes Trench Mortar during World War 1. The type stayed in circulation in the post-war US Army though several attempts to find a replacement ultimately came to naught. |
As a result, the US Army decided to work instead on bettering ammunition. In 1931, the US Army acquired four of the Brandt 81mm prototypes, and, after some slight modifications to suit American use and production methods, the mortar appeared formally as the "81mm Mortar, M1" in Army nomenclature. License production was handled by A.B. Farquhar Company, Pullman-Standard Car Manufacturing and Watervliet Arsenal.
Like the "lighter" M2 system, the M1 was made up of three main components - the firing tube, bipod and baseplate. When completely assembled, the M1 weighed in at 136lbs. Weight was distributed as follows: the tube made up 44.5lbs while the mount was 46.5lbs. The base plate itself was 45lbs. Overall length of the system measured in at 3 feet, 9.5 inches. Muzzle velocity was rated at 700 feet per second out of the smoothbore firing tube. A sustained rate-of-fire of 18 rounds per minute was possible, with the operator loading the M1 by dropping the prepared projectile into the muzzle. A firing pin at the base of the firing tube activated the projectile's primer and ignition cartridge (the projectile was dropped down the tube "fuze-end" first) and the corresponding action launched the round at the predetermined desired angle. The operator(s) need only to protect themselves after the projectile was dropped in the tube. This allowed for an excellent sustained rate-of-fire - a maximum rate-of-fire of 30- to -35 rounds per minute was achievable. The M1 maintained a minimum range of 200 yards and a maximum range of 3,300 yards. Elevation was +40 to +85 with a traverse of 14-degrees. The operator utilized an M4 collimator sight (same as on the M2 60mm derivative) fitted to the bipod for accuracy calculations and adjustments.
The M1 could utilize a variety of ammunition types beginning with the M43A1 Light HE (High-Explosive) round. The 6.87lb M43A1 maintained a fragmentation radius of 25 yards and featured a surface detonating fuze. The 10.6lb M45 and M45B1 Heavy HE rounds greater explosive punch at the expense of range (2,558 yards), this working from a delayed fuze. The 15lb M56 was another Heavy HE round of even greater explosive firepower with a more limited range of 1,300 yards. The fuze on these particular projectiles was adjustable as needed. Shells were stabilized along their flight path via fixed fins at their rear sections to compensate for the M1's use of a smoothbore firing tube (i.e. no rifling for inherent course trajectory).
Besides the conventional explosive rounds, the M1 could also make use of the 10.7lb M57 FS white smoke round out to 2,470 yards or the 10.74lb M57 WP (White Phosphorous), this also ranged out to 2,470 yards. The White phosphorous round was also equally adept at attacking infantry as an incendiary munition. The M301 was a useful illuminating round with an adjustable fuse and 60-second burn duration and deployable parachute, the latter helping to retard the projectile's fall.
Transport of the heavy M1 was solved through the use of a two-man hand cart designated simply as the "Hand Cart M6A1". This allowed the least possible amount of crew to move the mortar system about, allowing transport of the weapon into defensive or offensive positions as required with relatively little pain. Another option was to have the system towed via mule by way of a specially-devised harness. Despite its inherent weight drawback of the M1 kit, the firepower of the mortar offset any negatives especially when supporting artillery would not be made available in a given operation. A well-trained and experienced mortar team could engage targets in defilade, trenches, ravines or on slopes and, as such, proved lethal against enemies in both the European and Pacific theaters of war.
For another method of transportation, the M1 could most effectively be driven around on the back of an M3 Halftrack. These half-tank/half-truck "mutt" vehicles held the inglorious task of transporting just about anything under the wartime sky. From the rear of the M3, the M1 could be fired without the need for the crew and weapon to disembark from the vehicle, affording a certain level of "hit-and-run" tactical advantage. At any rate, this method of fielding the M1 proved most useful to any company commander.
A shortened version of the M1 was unveiled as the T27 "Universal" but this only appeared in limited numbers and was never ordered for mass production. A special tube extension system was also devised for the base M1, though this was hardly used in practice.
The M1 81mm Mortar was complimented in the field by the lighter M2 60mm Mortar beginning in 1940. The M2 was a more "portable" device that allowed for efficient close-support indirect fire and could operate closer to the actions of frontline infantry, its portability being a major plus.
