Projectile Details
Design InformationThe round is based off the BRG-15 15.5mm x 106mm round. Despite the success the BRG-15 round had achieved, and it's ability to pierce 13mm of steel at a 30 degree angle at over 1350 meters away (I.E. the ability to pierce the armor of almost any known APC at ranges well over 1000 meters), the project was canceled due to a lack in Finances, and was instead traded for the new idea of the FN P90. Still the BRG-15 demonstrated what high caliber machine guns were capable of, and the newer 15.5mm x 106mm round intends to expand upon it's original capabilities.
Bullet CompositionThe round is either completely filled with depleted uranium (and has a tombac jacket coating with a fine layer of teflon sprayed on the outside) or it is an explosive round. The Uranium round, being a complete dead weight, is capable of piercing 21mm of steel at a 30 degree angle at over 1350 meters away, or essentially be capable of piercing the armor of almost any modern APC.
Explosive 75 gram 15.5mm x 106mm
High Explosive Incendiary/Armor Piercing Ammunition (HEIAP) is a form of shell which combines both an armor piercing capability and a high explosive effect. In this respect it is a modern version of armor piercing shell. The ammunition may also be called Semi-armor piercing high explosive incendiary (SAPHEI).
Typical of a modern HEIAP shell is the NM142 MP Mk 212 Mod 0 round designed for weapons such as heavy machine guns and anti-materiel rifles.
The primary purpose of these munitions is armor penetration and extended damage past pure kinetic energy, but unlike SLAP rounds (Saboted Light Armor Penetrator) which get their armor piercing ability from the propulsion of a smaller tungsten heavy alloy bullet from a larger barrel using a sabot with much more energy than is usually possible from a smaller round, HEIAP munitions use high explosives to "blast a path" for the penetrator. The special effect is developed when the round strikes the target. The initial collision ignites the incendiary material in the tip, triggering the detonation of the HE charge. The second (zirconium powder) incendiary charge will also ignite. This burns at a very high temperature, is not easily extinguished, and can last for 30 seconds.
The remaining element of the round is the tungsten carbide penetrator. This has a large amount of kinetic energy and will penetrate the armor as solid-cored armor piercing shot would. This will take some of the incendiary material through the armor. The MK 211 is claimed to penetrate up to an inch (25.4mm) of rolled homogeneous armor.
The triggering of the explosive charge is dependent upon the resistance of the target. If the target offers little resistance then the lack of frictional heating will prevent the incendiary from igniting and the high explosive from detonating.
Larger guns such as the British 30 mm RARDEN cannon fire APSE (Armour Piercing Special Effects) shells which are an armor piercing round with added HE effect.
This round is usually identified by a green over white paint tip mark. A rarer occurrence of a green–over red–over white paint mark scheme indicate the tracer version of this round. These tracer versions are usually only seen on cartridge feed belts in naval applications.
The headstamp on the casing can also help to identify the round as Raufoss and some common headstamps include, but not limited to: HXP89, WCC94, and FN91; or HXP, WCC, LC, or FN with different two-digit numbers as production year suffixes.
The round itself is a 75 gram container. It is nearly exactly the same weight and mass of the original round, although the dispersions of the densities of the material is vastly different. While obtaining slightly different ballistics due to the density change than an ordinary round of it's kind would, in an ordinary case, the minor difference in over-all ballistics path is mostly negligible (a .025 inch movement to the right at 600 yards). This is in part becuase the round detonates on impact, both igniting the 4000 degree zirconium, setting off the C-4 explosive, the force of both of these more than compensating for any change in accuracy, and also becuase both these explosions themselves send the carbon tungsten penetrater into the material at such a rapid velocity when combined with the initial kinetic energy that slightly changing velocity while in flight becomes close to irrelevant.
The round is fully capable of penetrating 40mm of rolled homogeneous armor at a 30 degree angle at over 2000 meters and creating a massive hole in the sheet of armor, meaning that the round can fully destroy any current APC and kill the units inside with continued fire (20-100 rounds) at over a mile and a half away.
