20mm Casless Hispano Details
The weapon boasts a number of improvements over the 20mm Hispano cartridge, but is overall based on it's fundamental designs. The round has 70,000 joules in comparison to approximately 50,000 of the previous cartridge, and a higher velocity of 1040 m/s with a 130 gram cartridge than the previous 840 or 870 m/s velocity. This is largely achieved by using more powerful gunpowder, a stronger more resilient barrel material, and an enlarged muzzle break designed to keep the recoil of the weapon down, on top of other recoil reducing mechanisms. The firearm is coated in a finish that reduces friction, and use a dual recoil spring with a hydraulic recoil buffer and recoil buffer similar to the Hk45, which makes the action smoother and reduces felt recoil by approximately 30%. These features help keep the recoil controllable, however as the weapon is most commonly mounted on tripods or vehicles, this largely designed as a means to keep the weapon small. The weapon is only approximately 105 pounds, which is significantly lighter than many machine guns of comparable power, and is only slightly larger than a .50 caliber browning machine gun. The ammunition of the Hispano 20mm is .6 pounds, while the caseless rounds are approximately .4 pounds, which is much heavier than the .50 caliber round at approximately .25 pounds. Nonetheless it is more powerful, possessing approximately 3.5 times the power.
The round has a
relatively high ballistic coefficient of 2.35 and 2.15, higher than the .50 caliber cartridge at 1.05 and 1.35. Designed specifically to have as high a BC as possible, the standard 130 gram projectile has a BC of 2.15, and the 55 gram APDS round has approximately 2.35, due to it being skinnier and more aerodynamic. As a result of it's use as an anti-aircraft weapon and it's high weight, it has an extremely long range, longer than that of the .50 caliber round. The weapon uses both high explosives and kinetic energy cartridges, relying upon KE armor piercing sabot rounds made of hardened depleted uranium to pierce spaced armor, and high explosive rounds to defeat ordinary armor, infantry, aircraft, or other light vehicles. The 20mm rounds are based on the original 20mm Hispano rounds, but includes air-bursting rounds, shaped charge projectiles, armor piercing sabot rounds, and other variants. The weapon function both as a grenade and a rifle round, allowing it to fulfill the role of both an automatic grenade launcher and machine gun. The weapon's versatility allows it to replace multiple weapons on the battlefield, chiefly the 40mm automatic grenade launcher and .50 caliber machine gun, although both are used. The grenades are similar in design and construction to the 25mm x 59mm grenades designed for the ATK program, but are 20mm and designed for higher velocity, longer range use instead. The weapon uses the same technology, to allow for air bursting cartridges designed to take out infantry.
At 5075 yards (2.9 miles) the Armor piercing sabot cartridge still has the same power as the .50 caliber BMG at point blank range, and can easily pierce through the same level of armor as armor piercing .50 BMG rounds. The Armor piercing discarding sabot (APDS) round is made of depleted uranium, which is incredibly dense and has a very high hardness; the round is also flammable and fragments in to smaller, razor sharp pieces on impact, being capable of igniting fuel and ammunition, as well as metal when it oxidizes. The rounds are about as hard and dense as tungsten, but cheaper, and with somewhat better properties. Despite being weakly radioactive, they also pose less of a health hazard than tungsten, which comparatively is more likely to cause cancer than Depleted uranium. These rounds make good anti-aircraft weapons due to their high velocity and good overall performance, and have a maximum range of approximately 7.5 miles, although the effective range is much shorter than this (approximately 5 miles). The rounds can penetrate through approximately 1.125 inch of RHA steel at 1000 meters with 30 degrees of obliquity, and vary in performance based on the target material, working better against spaced armor but doing substantially worse against ceramic or chobham armor.
The 20mm hispano air bursting rounds have a substantialy shorter range due to their lower velocity than the tungsten armor piercing rounds, but it is much further than the 25mm x 59mm rounds. With the 25mm x 39mm rounds having a range of 2000 yards (1.25 miles) despite a velocity of 450 m/s, the 20mm Hispano has an effective range of approximately 5075 yards (2.9 miles) when using the air bursting function. The Air-bursting dual-purpose (ABDP) cartridges also possess an impact fuze, that will cause the rounds to detonate on impact with the target, igniting the armor piercing shaped charge warhead and dispersing the fragmentation. Like the 40mm Dual-purpose cartridge, the fragmentation is more ideally shaped and the spread pattern more ideally spaced to increase the lethal range of the shrapnel, and the explosive force of the shaped charge that is normally wasted with shaped charge rounds is used instead to disperse fragmentation, giving it the capability of both armor penetration and fragmentation dispersion. In this way, the dual purpose rounds possess the ability to be used with an air-burst effect, be impact detonated, or be used with an armor piercing shaped charge jet, providing all three capabilities in a single cartridge. This design is virtually as effective as cartridges designed for a specific role, and also has the benefit of avoiding leaving behind unexploded ordinance on the battlefield with the impact fuse and timer.
Typically, the weapon is deployed with both armor piercing discarding sabot rounds (APDS) and high explosive dual purpose air bursting rounds (ABDP), but other rounds can be used. Due to the high versatility and good performance of these rounds, they typically are deployed in tandem, and the user can choice between their choice of the two cartridges to fulfill virtually every role needed by the vehicle, from anti-aircraft, to anti-vehicle, to anti-infantry purposes. Tracer variants exist for both cartridges, but are rarely used due to the use of an infrared laser range finder instead, which is typically paired with the gun, removing the need for a tracer. As the air bursting rounds rely upon a thermal vision scope and infrared laser system, typically this is used to tracked the rounds over a tracer cartridge, which makes it less visible to the enemy and removes the need for specialty tracer cartridges.
