General Dynamics XM307
| General Dynamics XM307 | |
|---|---|
|
|
| general information | |
| Military designation: | XM307 |
| Country of operation: | United States |
| Developer / Manufacturer: | General Dynamics |
| Development year: | 1994-2008 |
| Manufacturer country: | United States |
| Model variants: | XM307, XM312 |
| Weapon Category: | Machine grenade launcher |
| Furnishing | |
| Overall length: | 1328 mm |
| Total height: | 182 mm |
| Total width: | 251 mm |
| Weight: (unloaded) | 22 kg |
| Barrel length : | 638 mm |
| Technical specifications | |
| Caliber : | 25 × 59 mm |
| Ammunition supply : | Ammunition belt |
| Cadence : | 260 rounds / min |
| Fire types: | Single and continuous fire |
| Visor : | 5-way ZF + IR + LEM |
| Closure : | Turret lock |
| Charging principle: | Gas pressure charger |
| Lists on the subject | |
The General Dynamics XM307 is a machine grenade launcher developed as part of the Small Arms Master Plan (SAMP) by General Dynamics, Primex Technologies, Dayran and Raytheon to replace the US Army's 40 mm machine grenade launchers Mk 19 and M2 machine guns . Since the weapon system in the Small Arms Master Plan is listed as Objective Crew Served Weapon (OCSW), the XM307 is usually also referred to as OCSW. In 2003 the weapon was renamed Advanced Crew Served Weapon (ACSW). The program was discontinued in 2008 without giving any reason.
history
As early as the late 1980s, the US armed forces came to the conclusion that the development of firearms with conventional projectiles, which derive their energy from the mass and the speed of the projectile, had reached its zenith. The new concept should therefore be based on air-igniting grenades as the main combat weapon , the effectiveness of which results from the explosion and the fragmentation effect of the projectile and whose combat power does not decrease with distance. This also opens up other possibilities, such as fighting opponents behind cover or inside buildings.
The first considerations for the development of the stationary two-man weapon began in 1992. The name Objective Crew Served Weapon (OCSW) was used for the system from 1994 onwards. The specifications were completed in 1995. It was determined that the weapon had to fire 25 mm ammunition with at least 250 rounds per minute and an effective range of 2000 meters. The ballistics computer should program the ammunition, take into account the muzzle velocity of the projectiles and have a target tracker and laser range finder. As part of the Small Arms Master Plan (SAMP), it was intended to replace the 40mm Mk 19 machine grenade launcher and the Browning M2 .
In the meantime, General Dynamics Armament and Technical Products was commissioned to develop the 25mm weapon along with the tripod. Primex Technologies was the main contract partner of the Department of Defense and responsible for the integration of the systems. Primex was also mainly responsible for the development and manufacture of the 25 mm ammunition . The Dayran company was also involved in the project and developed the firing mechanism for the grenades. Raytheon developed the fire control computer. In 1999, unmanned attempts to fire the one-man version with a bipod , shoulder rest and improvised telescopic sight were carried out for the first time. The two-man version was mounted on an HMMWV and also fired unmanned.
In January 2001, Primex Technologies was allocated US $ 17 million from the defense budget to build three advanced technology monstators and ammunition. In June 2002 these were shot tested at the Aberdeen Proving Ground . In 2003 the program was renamed Advanced Crew Served Weapon (ACSW) and on January 7, 2003 General Dynamics demonstrated the ability to convert the ACSW to a machine gun with the 12.7 × 99 mm NATO caliber . The system, initially known as the XM307 / K50, differed from the grenade weapon in only five parts and was intended as a substitute function if 25 mm ammunition were not available. In 2004 the ACSW was able to achieve all specified parameters.
In the same year, $ 117 million was withdrawn from development because the Joint Requirement Oversight Council had not yet approved the performance requirements. The financing therefore had to come from other means. On February 16, 2004, General Dynamics received two development contracts worth $ 7.1 million to further test and improve the weapon. In the same year, further contracts for 90 million US dollars were signed, so that in May 2005 the development of a remote-controlled version for vehicles could begin. That year, test shots with the 12.7 mm version - which was now referred to as the XM312 - took place at the Grafenwoehr training area .
In 2007, additional contracts for the ACSW program for $ 90 million were signed. However, the program was canceled in 2008 without giving any reason. The XM312 was also affected, although a newly designed version without a ballistic computer called the XM806 was further developed until 2012. Then this program was also terminated and additional Browning M2 were procured instead .
overview
Heavy team weapons are used quasi-stationary by the infantry to defend positions or to support their own units advancing with fire. The machine guns and grenade launchers used for this have specific advantages and disadvantages: Heavy machine guns are well suited to destroying light and unarmored vehicles at great distances; they can also be used to penetrate obstacles. However, due to their low rate of cadence and precision , such weapons are less suitable for fighting exposed infantry . Machine grenade launchers, on the other hand, are very suitable for fighting exposed infantry, as the shell hail covers a large area with splinters when it hits. However, due to their low speed and precision , these weapons are less suitable for fighting lightly and unarmored vehicles at great distances .
The idea now was to combine the advantages of both systems: Air-igniting grenades are more effective than contact detonators, since terrain obstacles and bumps no longer offer the enemy protection from flying fragments. The shells can be made smaller, which results in an increase in muzzle velocity with the same recoil impulse. This increases the speed, which makes it possible to fight opponents at great distances that were previously only reserved for heavy machine guns. In various combat simulations with the OCSW against enemy eight-person squads with PASGT , a clear advantage over the established M2, M240 , Mk 19 and M249 weapons was achieved. Against standing opponents up to 400 m the difference to the Mk 19 was moderate, at larger distances and against lying opponents the advantages over all other weapons were overwhelming: On average (from 200 to 2000 m combat distance) the OCSW was 4- to 6- times more effective than a Mk 19, 11 to 20 times more effective than an M2, 8 to 11 times more effective than an M240 and 14 to 26 times more effective than an M249. It was 49 times more effective against people in cover than with the other weapons.
Thanks to the ballistic computer and the precise weapon, which was more like a machine cannon with a low muzzle velocity (425 m / s), the OCSW was able to work with pinpoint accuracy even at greater distances, which also enabled high-value targets ( High Payoff Target, HPT ) such as enemy snipers and MG troops could be destroyed up to 2000 m away. Thanks to the precise fire control and the effective ammunition, the weight of ammunition required for a 30-day battle could be reduced by an average of thirty times, so that logistics effort and costs could be saved.
technology
construction
The XM307 consisted of three main parts: the mount , the grenade launcher and the ballistics computer. There were also ammunition boxes that could be mounted on the weapon. The total weight of the system without ammunition was about 22 kg, of which the tripod made up about 6 kg. This lightweight part was height-adjustable and provided with a ground spur to reduce weight . The grenade launcher, which without a ballistic computer weighed around 13 kg, could be placed on the mount. The ballistic computer itself weighed about 3 kg and was practically never separated from the weapon. The weapon was designed to be carried and operated by a two-person team. Including ammunition, each soldier then carries just over 16 kg.
The shell of the grenade launcher is made of steel, inside of which the repeating mechanism runs. The barrel length is 638 mm with an effective muzzle brake at the end. This is a gas pressure charger with a sliding barrel and a rigid locking mechanism that is made by a rotary head lock. When the shooter pulls the trigger on the handle, the bolt carrier is moved forward and inserts a new cartridge into the chamber. The barrel and slide then move forward, locking the weapon. The fed cartridge is ignited when the barrel and slide are already locked but are still moving forward. The movement impulse thus counteracts the recoil impulse. After the shot, the bolt and barrel move back together, the bolt head turns and unlocks with the barrel. The barrel then stops while the bolt carrier moves further back and ejects the cartridge case. If the shooter continues to hold the trigger, the cycle is repeated until the M15A2 ammunition belt is used up. The rate of fire was 260 rounds per minute, and an ammunition box could hold 31 cartridges and could be attached to the left or right of the weapon.
The weapon could fire all kinds of ammunition in the 25 × 59 mm caliber ; later versions even had the option of a double belt feed to fire two types of ammunition alternately. The XM312 variant in the 12.7 × 99 mm NATO caliber could be implemented without any problems, as both types of ammunition have roughly the same recoil impulse. The weapons are therefore 95% identical, only five parts had to be changed, which could be done in less than 90 seconds. The barrel length here was 838 mm. Both systems - XM307 and XM312 - achieved an overall precision (weapon and ballistic computer) of less than 1.5 mil . Two servos were attached to the grenade launcher , with the help of which the angle of rotation and elevation of the weapon could be changed in single-stroke steps using the buttons on the handles. In addition, the servos supported the shooter's movements.
Ballistic computer
The gun's ballistic computer was developed by Raytheon and used the same technology as the OICW's Target Acquisition / Fire Control System (TA / FCS) , but was not identical to it. The nameless device at the rear end of the weapon, which was only called Target Acquisition / Fire Control (TA / FC), took over many features of the HK XM29 such as an integrated video and infrared camera, which saw moving targets and marked them with a rectangle, moving with the destination, or the built-in electronic compass . The information and representations could be manipulated using buttons on the handles at the end of the weapon or using buttons below the eyepiece .
There were fewer viewing modes of the fire control computer, only a direct view with 5x magnification and a field of view of 9.5 ° was available. In the upper area of the reticle , an interrupted crosshair was shown as a stop. Thanks to the built-in thermal imaging device ( FLIR ), the display could also take place in the infrared. To calculate a fire control solution, the distance to the target was determined with a laser rangefinder, the beam of which could be swiveled by the computer. The distance was measured with an accuracy of ± 1 meter. Using the buttons at the end of the weapon, the measured distance could be changed manually and the firing mode of the grenades selected. An algorithm then calculates and corrects the lead point with the help of the distance of the target, the elevation and rotation angle of the weapon, the environmental conditions, the detonation mode and the trajectory of the grenades. After the calculation has been completed, another crosshair appears automatically as a lead point in the correct position on the display, in order to guarantee a high hit rate with the first shot when the shooter points it at the targeted target. The laser remains automatically aimed at the target and the distance is measured continuously, even if the target or weapon is moving. The lead point is calculated and displayed in real time. The laser can control any target in the field of view ( full FOV laser steering ).
The grenades were programmed using contact strips. The only option available was to give the grenade a distance to ignite air. The percussion fuse was independent of this and was only armed after about 50 m. This was necessary because the grenade gained energy through programming. The delay detonator was thus omitted.
Web links
Individual evidence
- ↑ a b c globalsecurity: XM307 Advanced Crew Served Weapon
- ↑ a b c d e globalsecurity: Advanced Crew Served Weapon (ACSW)
- ^ A b c John H. Edwards: Force Effectiveness Leap with OCSW . Ed .: Department of Defense. 2000.
- ↑ EUCOM: Soldiers test new weapons at Grafenwöhr , October 4, 2005 ( Memento from April 24, 2014 in the Internet Archive )
- ^ A b John H. Edwards: Force Effectiveness Leap with OCSW . Ed .: Department of Defense. 2000.
- ↑ Williams, Anthony G. (2008) Defense Management Journal , Issue 41 ( Memento from October 25, 2012 in the Internet Archive )
- ^ John H. Edwards: Force Effectiveness Leap with OCSW . Ed .: Department of Defense. 2000.
- ↑ a b XM307 Program Reliability Growth, Ammunition Development and Advanced Technology Demonstration Tests , 2003 Small Arms Symposium & Exhibition National Defense Industrial Association May 13, 2003 ( Memento of December 28, 2016 in the Internet Archive )
- ↑ 2003 Objective Crew Served Weapons (OCSW) , Small Arms Symposium & Exhibition National Defense Industrial Association May 13, 2003 ( Memento from December 28, 2016 in the Internet Archive )
- ↑ a b General Dynamics: XM307 ACSW Dual Feeder and Receiver Design for Rough Handling , 2007 ( Memento from March 4, 2016 in the Internet Archive ) (PDF; 1.4 MB)
- ↑ a b c d PM Crew Served Weapons Overview for the Small Arms Symposium & Exhibition , May 7–10, 2007 ( Memento from March 4, 2016 in the Internet Archive ) (PDF; 6.5 MB)
- ↑ 2006 Gun and Missile Systems Conference & Exhibition National Defense Industrial Association , March 30, 2006 ( Memento of December 21, 2016 in the Internet Archive ) (PDF; 1.6 MB)
- ↑ globalsecurity: XM1019 High Explosive Air Bursting (HEAB)