Possible Future For Russian Ammunition – Lightweight 5.45

As ammunition development progresses, various approaches are being explored. Some manufacturers focus on creating stronger cartridge cases to achieve the necessary pressure for lobbing projectiles at adversaries. Others prioritize making ammunition lighter, making it easier for soldiers, simplifying logistics, and reducing costs. This weight reduction benefits military operations and presents significant economic advantages for taxpayers, fostering optimism about the new designs and their potential to revolutionize the defense industry.

Russian Ammunition @ TFB:

5.6x60mm Experimental Soviet Cartridge New Russian 6.02×41 Cartridge and Prototype Rifles (AK-22 and Mini SVCh) Modern Personal Defense Weapon Calibers 007: The 7.62x25mm Tokarev Russian 7.62x25mm Factory Ammunition with Backwards Loaded Bullets from 7.62x39mm

This is where a lightweight 5.45×39 cartridge comes in a recently filed (2023) Russian utility patent (RU 218872 U1) by the Penza Military Academy. The patent describes “reducing cartridges’ mass to increase servicemembers’ survival rate.” This is done by reducing the weight by replacing the front of the cartridge with a polymer casing or sleeve while retaining the steel base or cup of the cartridge, providing maximum strength during firing and reliable extraction.

Math

The proposed material for the 5.45-mm cartridge case is polyamide RA6, which would reduce its weight by 30.4%, resulting in a total weight of 15.3% less than that of the standard 5.45mm cartridge. So, if the standard loaded cartridge weighs 10.5 grams, the hybrid loaded cartridge should weigh about 8.9 grams. This would allow for an ammunition loadout of 240 rounds weighing just 4.7 lbs. (2.1 kg) compared to the current loadout of 5.5 lbs. (2.5 kg). Any soldier would be happy to lose weight if it does not diminish the weapon’s reliability. In the past, the

The Soviet Union dabbled in lightweight ammunition and even went a step further with caseless ammunition in the AB-3 rifle.

Heat

This proposed polymer-cased ammunition may offer advantages in heat transfer compared to traditional metallic-cased ammunition. The polymer casing is designed to insulate and manage the thermal effects of rapidly expanding hot gases from combustion, which can help lower the chamber and barrel temperatures. This could reduce the risk of cook-offs and increase the lifespan of the chamber due to reduced heat generation. While the exposed steel base or cup will still conduct some heat, it will likely do so to a lesser extent because of the decreased metallic surface area.

The proposed lightweight polymer casting is said to have increased the reliability of extraction and obturation at a high chamber pressure of over 3000 kg/cm (42,670 psi) by changing its surface profile. At the same time, the AK74 has a typical chamber pressure, depending on the ammo, of 55,00 to 58,000 psi. The proposed model reduces the sleeve’s friction force against the chamber’s surface during extraction.

This approach addresses the disadvantage of this steel cartridge case: the low strength of the sleeve wall body, which leads to periodic and unforeseen ruptures of the body during the extraction of a spent case.

Outline

The proposed technical solution consists of a cartridge base made of cold-rolled steel. The base is 10mm high and is said to be rigidly connected with adhesive to the polymer in the base section. The adhesive proposed to adhere the casing to the base is Loctite 460, with an operating range from -40° F (-40° C) to 176° F (80° C). Its operating range and design with an increased number of parts increase failure points in the design. So this is a give-and-take for a lighter-weight combat load out. The proposed Polyamide RA6 operating ranges from -40° F (-40° C) to 194° F (90° C). However, the increased number of parts in the design could lead to more failure points, which is a potential drawback of this technology until it can be made reliable. 

The polymer section has a height of 32.8mm, a maximum wall thickness of 0.829mm at the bottom of the sleeve, a minimum wall thickness of 0.399 mm, and a total length of 39.8mm.

Future

It is unclear whether the Russians will successfully adopt polymer hybrid ammunition. If it is successful, this could significantly impact the design and use of ammunition, providing economic and tactical advantages in military operations. The technology and benefits are there, and we will have to wait and see if this aligns with RF MOD requirements. A reduced combat load could lessen the burden on soldiers and improve their maneuverability; however, this weight reduction will be replaced with additional ammunition, which isn’t necessarily a negative outcome. The typical load-out serves as a suggestion and a baseline for the soldiers to build on. Having had the chance to test the NGSW RM277 a few times, I can see the advantage of using polymer ammunition, and it’s unfortunate the US didn’t show more interest in the concept.