A specialized sub-caliber projectile for use against light vehicles has been patented in Russia.
Recently, apparently in connection with the special military operation in Ukraine, domestic specialists have been patenting some rather interesting defense inventions. One of them is a fin-stabilized armor-piercing subcaliber projectile for tank cannons adapted for the effective destruction of light military equipment.
Instead of an introduction
It's no secret that armor-piercing discarding sabot (APFSDS) rounds used in tank ammunition have a rather powerful after-action effect. When such rounds penetrate armor, a large number of high-velocity fragments fly into the after-action space, injuring the crew, damaging the tank's internal equipment, and potentially igniting the fuel and causing a fire or detonation of the ammunition contents.
However, they can only be most effective against the relatively thick armor of tanks. This often doesn't work against the thin armor of light vehicles like infantry fighting vehicles or armored personnel carriers, as the projectile's core doesn't have time to sustain significant damage and generate a massive fragmentation field (most of the fragments are secondary fragments, from the armor). As a result, the projectile often simply penetrates the vehicle, causing minimal damage (compared to the damage a projectile would inflict on a tank).
This, in fact, is what prompted the gentlemen from the Boris Yeltsin Ural Federal University to develop a subcaliber projectile with enhanced behind-the-barrier effect. And, to forestall any questions about whether the information might be classified, we'll add: the patent for the projectile is published in an open database, so it's not classified in any way. A link to it will be provided at the end of this article.
Fluoroplastic instead of explosives
So, what do the inventors propose?
They plan to increase the effectiveness of the projectile beyond the barrier by increasing fragmentation and providing an additional incendiary effect. However, the proposed design does not use explosives, as found in chambered armor-piercing shells, which have long since become obsolete, due to the dangers of handling them.
Instead of explosives, the use of mixtures of fluoroplastic and metal in powder form is proposed. At a certain pressure, these "cocktails" produce an explosive release of energy and an exothermic reaction with the release of heat. For example, a fluoroplastic/titanium mixture reacts effectively at pressures above 28 GPa, while a fluoroplastic/aluminum mixture reacts effectively at 21 GPa. The graph below clearly illustrates this.
Achieving the reaction coefficient (unit) at different pressures for mixtures of fluoroplastic with aluminum and titanium)
The mixture in the projectile doesn't require any additional "detonators" to increase the pressure to the required levels—a high-speed impact with the armor is sufficient. To achieve this, one could use the design of existing projectiles (like Mango) and insert the mixture in place of the armor-piercing core. As an example, the projectile proposed by the authors is shown below.
Essentially, it consists of a metal body containing a "reaction core" made of a fluoroplastic-aluminum mixture. An armor-piercing tip made of a heavy tungsten-based alloy (uranium is also possible) is screwed into the nose, and on top of that is a ballistic tip made of a light alloy.
1 - metal body, 2 - driving device, 3 - polymer obturating belt, 4 - obturator of the driving device, 5 - stabilizer, 6 - tracer, 7 - reaction core, 8 - armor-piercing tip made of heavy alloy, 9 - ballistic tip.
The principle of operation of the projectile is quite simple.
Upon exiting the barrel, the projectile's active portion (the "arrow" itself with its fins) separates from the leading element. Upon impact with armor, the ballistic tip collapses, and the armor-piercing tip, made of a heavy alloy, engages, penetrating most of the armor. Due to the high impact velocity with the armor barrier, the required pressure is generated within the fluoroplastic and aluminum mixture.
Quote from the patent:
As a result of compression of the core made of reactive material during a high-speed impact, conditions for thermal-oxidative destruction and radial expansion of the reactive material are simultaneously created, transmitting the compression pressure to the inner walls of the housing.
Further progression of the compression process leads to the exothermic decomposition of the reaction material with a large release of energy, fragmentation of the metal body of the projectile, an increase in the cavity and the release of high-speed remains of the projectile and a cloud of fragments into the fighting compartment of lightly armored vehicles with a large angle of dispersion.
Further progression of the compression process leads to the exothermic decomposition of the reaction material with a large release of energy, fragmentation of the metal body of the projectile, an increase in the cavity and the release of high-speed remains of the projectile and a cloud of fragments into the fighting compartment of lightly armored vehicles with a large angle of dispersion.
Essentially, the shell's active portion is torn to shreds by internal pressure upon penetration, producing a massive amount of fragmentation from both the shell and the armor. This is accompanied by a significant incendiary effect inside the combat vehicle, which can lead to combustion of fuel and technical fluids, and in some cases, ignition and detonation of the ammunition.
Conclusions
The invention is certainly interesting. Essentially, it's a domestic version of Western PELE (Penetrator with Enhanced Lateral Effect) projectiles, which are effective against light armored vehicles. Moreover, it's feasible to establish production even with existing facilities. But, as the saying goes, "It's possible, but why bother?"
And it's not that, as the fashionable saying goes, "tanks don't fight tanks and other vehicles anymore"—of course, they don't fight much now, but in future conflicts they very well could. The issue here lies in a slightly different realm—a practical one.
Firstly, these shells are designed exclusively for destroying light vehicles and, perhaps, not yet very substantial fortifications. They are useless against tanks—they won't penetrate them. This means that the ammunition is essentially highly specialized, and its use poses certain challenges in terms of expanding the ammunition loadout.
Secondly, of course, sub-caliber projectiles, including those discussed in this article, are much easier to hit due to their high muzzle velocity, requiring minimal adjustments when firing. However, for engaging light armored vehicles, a standard high-explosive fragmentation projectile is quite suitable, and can inflict far more damage.
So the thing is undoubtedly interesting, but it’s unlikely that they will ever produce it here.
Source of information and images:
Patent for invention
Information