According to the "Defense Bulletin" website reported on October 11, the United States General Dynamics Ordnance and Tactical Systems Company said that the company successfully tested four XM1210 (XM1113ER) high-explosive rocket auxiliary extended range ammunition for the U.S. Army's Future Extended Range Cannon (ERCA) system at the Yuma Proving Ground in Arizona on October 2. The munition demonstrates the ability to have a range of more than 70 kilometers. The ERCA system, also known as the XM1299, is based on the new American M109A7 self-propelled howitzer, which began production in 2018. But the XM1299 can be seen as an entirely new system, with a new turret, a chassis for the U.S. military's existing 155mm caliber M109A7 PIM self-propelled howitzer, a new 58-caliber gun, a new automatic ammunition loading system, and many other new systems. The weight of the XM1299 is similar to that of the M109A7.
The XM1299 features the chassis and turret of the active M109A7 gun, a 675-horsepower Cummins VTA903E-T675 engine and a HMPT-800-3ECB gearbox, and a chassis with 6 pairs of load wheels, enhancing its versatility with the M2A4 vehicle.
The XM1299 turret underwent a major blood change and was fitted with a 58×inches XM907 155mm gun. The gun is a variant of the M777A2 howitzer, with a barrel length of 9 meters and a chamber volume of 27 liters. The gun was also equipped with a semi-combustible cartridge XM654 Super Charge and a brand new small charge XM659. The range of the ordinary grenade is estimated to be about 50 kilometers, the range of the XM1113 rocket booster range shell is 70 kilometers, and the M1156 precision guidance fuze can also be installed, with GPS guidance capability. Both figures are capable of dealing with 52-caliber self-propelled guns of China and Russia. The new XM1155 rocket extended range gliding terminal guided shell can be deployed in the middle of the trajectory through the bottom of the exhaust flight to increase the range, the range will exceed 100 kilometers, the use of MEFP high-explosive warhead, can be generated by the explosion of the formed projectile to hit the target. A later test fired a total of two XM1113 rocket extended range grenades and two Excalibur guided artillery shells, and the test result was that the range of the rocket extended range grenade met the theoretical requirements, but the landing point deviated from the target by more than 600 meters, showing insufficient accuracy; the "Excalibur" guided shell accurately hit the car target after flying 65 kilometers, and the strike accuracy was quite high. Through the fire control system, the XM1299 can achieve 8 rounds of simultaneous bounce.
Excalibur guided the cannonball
On June 24, 2019, the U.S. Defense News reported that Norwegian Nammo will work with Boeing to develop long-range artillery shells equipped with ramjet rocket engines. Nammo has previously shown shell samples with a maximum range of up to 100 km, a ram engine that can work for 50 seconds, and a top speed of about Mach 3, but the charge is only 5 kg. The shell also has the ability to fit on the XM1299, but it must be very expensive.
In our memory, American armored vehicles are always indispensable to the "human flesh loader" black uncle, and how can such a tall car as XM1299 be so dirty! The third class decided decisively to equip the horizontal automatic loader, with the ammunition arranged in the tail compartment in a chain, and the shells and cartridges were placed in each link. When loading, turn the bullet chain to the corresponding position, the pusher can be loaded by moving the push bullet up and down, not only the continuous rate of fire is greatly increased from 3 rounds / min to 10 rounds / min, but also can reduce the center of gravity of the vehicle, after all, adding such a long barrel must have an impact on the center of gravity.
The XM1299 extended-range gun prototype began firing range testing in 2018. At present, it is planned to start procurement from 2023 and start to be installed in 2024, and the XM1210 high-explosive rocket auxiliary extender bomb used this time is actually the XM1113ER rocket range extender ammunition just mentioned. Bottom row / rocket range increase technology is one of the main range extension technology of the current shell, the principle is to add a bottom row device and a rocket engine on the shell, the shell with this device after leaving the muzzle, due to the role of the bottom row device, reduces the vortex resistance of the bottom of the shell, after its loss of role, the rocket engine continues to work, so that the ammunition again to obtain a forward momentum, so as to achieve the purpose of improving the range. The projectile has a range of more than the existing 30 km to 40 km when fired from the existing 39 caliber 155 mm gun, which can improve the safety of soldiers on the battlefield, and can also be equipped with the existing M1156 precision guidance components to provide quasi-precision strike capability. XM1113 rocket range extended ammunition is expected to begin small-volume trial production in fiscal 2022. The XM1113 mainly increases the range by increasing the thrust of the rocket engine and optimizing the shape of the projectile, and its high-performance rocket engine is nearly 3 times the thrust of the existing M549A1 rocket range-extended ammunition, while the streamlined projectile shape can also reduce drag, which can be fired by the active M777A2 howitzer or by the M777ER howitzer under development. The XM1113 shell uses a charge that meets the standard of blunt ammunition, which has better stability, less response to external stimuli, and a reduced chance of martyrdom, of course, to achieve a range of 70 kilometers, it also requires the assistance of M654 super launcher. The shell is cheaper than the stamped shell of the castle in the air, and the accuracy after adding the guidance component PKK component should not be bad, which is a good choice for the US military to afford.
On September 16, 2021, the U.S. military announced at the Picatinny plant that a new generation of 155 mm/58 self-propelled howitzer prototypes manufactured under the Extended Range Artillery (ERCA) program will be delivered to the military for force testing, a total of only 2, and will not begin trials in the U.S. Army until 2023, delivered to the 4th Iron Mine Battalion (4-27FA) of the 27th Field Regiment Artillery of the 2nd Armored Brigade of the 1st Armored Division, and the U.S. Military will not be able to test the troops until the end of the trial until the end of the trial. It seems that this test will not be completed for a while and a half!