Semoventi di artiglieria M-109
The M109 is an Italian version of the American M109 self-propelled howitzer. The M-109 self-propelled artillery [Semoventi di artiglieria] was developed on the basis of a precise request from the US Army: to have a heavy howitzer with great mobility on any type of terrain capable of replacing the outdated M-44. The first M-109s entered service in the early 1960s and immediately proved the validity of the design. The M-109 was also constantly improved to update it to the evolution of operational needs. The 155 mm main armament was also improved with the adoption, starting from the A1 version, of the long-barreled M185 cannon characterized by a decidedly increased range. The subsequent A2 version incorporated further improvements on the weapon, pointing, ammunition and target acquisition systems.
The M109 self-propelled artillery vehicle was introduced in the late 1950s,has a large turret with 28 rounds and front engine, has an aluminum hull whichoffers some protection from small arms, a weight of 23-28 (depending on versions) tons; carries a light howitzer with a large muzzle brake, with a short barrel of approximately 23 calibres, for a range of 14 km. It can ford a river up to 1.8m deep,for greater depths an additional kit is needed, which requires a long preparation. The vehicle has been extensively updated to keep pace with technological advances.
The turret and hull have a welded aluminum structure, with a high cost but greater lightness. It is the same alloy used for the M113 troop transport, i.e. 5083. Maximum thickness is approximately 30mm and only protects against shrapnel and lighter bullets.
The pilot sits forward, to the left, the engine compartment is to his right, because the structure envisaged freeing up the entire rear for the needs of the artillery crew and cannon. The engine is a GM 8V-7IT, diesel (albeit without guarantee for great autonomy), with a front transmission. The pilot has the possibility to drive with levers and brakes in 1st and 2nd gear, with the semicircular handwheel for the 3rd and 4th.
The structure of the suspension is torsion bar, with a series of 7 wheels per track, without track guide roller, but only with a rear idler roller. The track, given the relative lightness, has a track width of 28 cm, while the wheels are rubberized. The hull is very high, compared to the tracks, and very spacious. Always in the hull there are infrared night guidance systems and an amphibious kit that allows, with long preparation, the crossing of stretches of water, moving only with the tracks. It consists of 9 pneumatic floats and 3 breakwaters.
Everything is mainly housed in a turret. This is totally closed, because NBC and protection from artillery shrapnel were among the requirements. The artillery was chosen not to over-stress the hull and turret, which are very light for such a system. The aluminum structure has a high cost but, if nothing else, a much less powerful and therefore economical engine is required for equal performance.
M109G
The M109G howitzer variant is equipped with a gun of 39 calibers in length, which provides a maximum range of 24-30 km. The M109G is the standard NATO model. The models produced in Italy, under license, correspond to this standard, It has an improved muzzle, with different rifling, redesigned by West Germany (hence the name of the version) for the needs of most European nations. The firing range is 18 km, but the barrel length remained the same, so it is not clear how credible this data is. In any case, the M109G self-propelled gun has an a vertical wedge, which allows to increase the rate of fire with respect to the shutter headwork. The length of the rifling is longer, and the shape of the muzzle brake is round instead of 'hammer'. This, together with the grenade launchers makes it easily recognizable.
The turret is large and rectangular in shape, with rounded sides and a hatch on the left. Its function is to house the M126 artillery piece , a howitzer that is a very distinctive weapon. The weight is extraordinarily low, the recoil mass is 1430 kg for a maximum recoil stroke of approximately 900mm. A high pressure 105/51 cannon has a mass of 1200 kg, yet it shoots projectiles only one third heavy (15 kg vs 43).
It lacks an anti-distortion thermal sleeve, but has a huge double light muzzle brake, and an even more characteristic structure, a kind of large cylinder,just behind, which acts as a smoke ejector. The gun has pressure relatively short, with 23 calibers in overall length, because it is designed to give as little torment as possible to such a light vehicle, and moreover equipped with a turret. The large muzzle brake has the function of reducing recoil forces.
The range is 14,320m, the bolt is of the threaded screw type, i.e. the old system, with the help of a semi-automatic ram for loading. The structure of the weapon is installed on a carriage capable of -5/+75 degrees, while the rotation and elevation have a hydraulic motor, with manually operated auxiliary handwheels. The recoil distance, depending on the elevation, can go from about 920mm with -3 degrees,at 59 with 75 degree lift, as possible by an adjustable hydropneumatic shock absorber system. The M117 targeting and observation periscope, an M118for direct fire, an M42 periscope and an M15 elevation dial.
In essence, a hull with high mobility was chosen to make hits reach the target, rather than relying on heavy long artillery with a hull that was too slow and awkward, which would have risked not compensating the possible range increase of 5–10 km. Or, it would have been necessary to delete the turret by relying on a barbette or an open emplacement (like the M107).
Ammunition is present in a total of 28, of the type HE, smoke, tear gas, nerve gas, sarin gas, Copperhead rocket assisted projectiles and the deadliest, those low-yield tactical nuclear weapons. The launch charges are separate from the projectiles, are variable and give motion to grenades weighing about 43 kg.
The defensive machine gun exists on a long mount on the roof,is the 12.7mm M2 HB with a total of 500 rounds, manually operated, and for the the rest also exist 3 smoke grenade launchers per side.
M-109L
By 2019 Leonardo had developed and tested a substantial upgrade package for the General Dynamics Land Systems M60A3 main battle tank and the M-109L self-propelled howitzer, built and tested using internal company financing for products aimed at the export market. The goal is to provide countries still using these armored vehicles with an affordable upgrade package that improves protection, propulsion and firepower.
Leonardo offers a radically updated version of the M-109L self-propelled artillery at extremely limited costs compared to the purchase of latest generation systems. The 155/23 caliber howitzer is replaced with the Italian-made 155/39 equivalent to that of the FH-70 towed howitzer, has a new fume extractor and can use standard and intelligent ammunition (such as the Leonardo Vulcano) in degrees of hit targets up to 30 and 40 kilometers.
The latest upgraded M109L has a 23 litre chamber and meets the Joint Ballistic Memorandum of Understanding (JBMOU). It is also fitted with a fume extractor and a new pepper box muzzle brake. The recoil system and equilibrators were modified to take into account the increased recoil and weight of the 155 mm/52 calibre ordnance. The breech mechanism is of the screw type, and a flick rammer is fitted with an adaption on the stroke of the rammer to fit with the longer chamber.
Maximum range depends on the projectile and charge combination, but firing a standard 155 mm M15A2 high-explosive (HE) projectile a maximum range of 30 km can be achieved, or an extended range ammunition could reach 40 km, according to Leonardo. The most significant range improvement would be firing the latest Leonardo Volcano 155 mm Ballistic Extended Range (BER) artillery projectile, which was type classified by the Italian Army and is ready for quantity production as soon as orders are placed.
Potential customers of the upgrade kit are the militaries of at least two dozen countries that still operate the M-109L.
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