Russia has long experimented with a 6mm cartridge dating back to 1913; unfortunately, or fortunately, the Russian government saw it as not worth changing calibers at that time. Fast forward to the 1980s with the 6x49 Unified hypervelocity cartridge, then again around 2015 with a reportedly reduced-velocity 6x49 for assault rifles. Once again, Russia is investigating a 6mm cartridge, this time for the future Russian assault rifle and possibly light machine guns (LMG). At least these are the ones we know about.
Russian 6mm Program: The Search for a New Ballistic Solution
Russian adopted 5.45 AM-17. By Lynndon Schooler.
The proposed 6mm cartridge
Kalashnikov Concern and Tula Cartridge Plant (TPZ) continue work on a new assault rifle cartridge. This has sparked new public interest after the publication of a Russian patent RU 2809501 C1. The Tula Cartridge Plant developed the new assault rifle ammunition in collaboration with the Kalashnikov Concern, and it received the working designation 6.02x41.
The 6.02x41mm intermediate cartridge is essentially a Russian version of the .243 caliber, as both share the same bore diameter. One notable feature is the reduced taper of the steel case, which the patent states is 1.0 to 1.5 degrees. This caliber bridges the 5.45x39mm assault rifle cartridge and the 7.62x54mm General Purpose Machine Gun (GPMG) cartridge. While it may not become the standard caliber of the future, it demonstrates a proof of concept for Russia as it explores the viability of a 6mm caliber 6.02x41, or the 6.02x43. The patent references a possibly longer cartridge case.
6.02x41 muzzle velocity and range. Photo from the patent.
One advantage of using a larger caliber for squad support weapons is the increased standoff range, ballistics, armor, and barrier penetration compared to its predecessor, as now you get better mass and velocity, not one or the other. Second, it lets infantrymen maintain the same combat load while only slightly increasing weight over the 5.45x39mm cartridge and the new magazine design, so no big change there.
Another advantage of the 6.02x41 cartridge is that it remains supersonic beyond 1,000 meters despite having a lower muzzle velocity than the AK-74. Between 200 and 1,000 meters, it experiences less loss in muzzle velocity than the 5.45x39 cartridge. The muzzle velocity of the 6.02x41 is 2,625 feet per second (800 meters per second), and it delivers a muzzle energy of 1,585 foot-pounds (2,150 joules) with a 103.4-grain (6.7 gram) projectile, resulting in similar performance to 6mm ARC. This projectile outperforms its predecessors by maintaining significant kinetic energy up to 1,000 meters. This information is derived from Russian patent RU2809501C1. However, the barrel length and twist rate used in this data remain unknown variables.
6.02x41 Energy and range. Photo from the patent.
Based on publicly available information, Russia developed multiple 6mm cartridge designs from 6.7x45, 6.02x40, 6.02x41, and 6.02x45mm cartridges during research into a new ballistic solution at the Tula Cartridge Plant in 2020-2023.
Over the years, Russia has been influenced to change calibers following WWII to 7.62x39 and the US involvement in the Vietnam War, where they obtained US weapons and ammunition, which led to the development of the 5.45x39. Again, the US NGSW program testing and adoption provided another nudge to push for a new cartridge.
Thoughts
Given Russia's current involvement in the war in Ukraine, it may take some time before we see further developments or the adoption of a new caliber. The initiative for the new cartridge was likely a response to the United States’ Next Generation Squad Weapon (NGSW) program, which utilizes a 6.8x51 caliber. However, this response has led to the development of an intermediate cartridge rather than a full-power rifle cartridge. The ongoing Russo-Ukrainian War may also have influenced this decision.
The testbed AK-22 has been modified from a first-generation AK-12 chambered in 5.45x39. This was used to reduce the prototype testbed production costs, whether they proceed with this prototype or a more modern system. Converting an AK-12 to the new 6.02x41mm caliber likely required a new bolt, bullet guide, magazine, barrel, and possible front trunnion modifications.
7.62x54 SVCh. By Lynndon Schooler.
Everything involves a give and take, and the 6.02x41mm cartridge effectively addresses the capability gap between assault rifles and GPMGs. While the NGSW M7/M8 reduces ammunition combat load and increases weight for added performance, the 6.02x41mm cartridge, and, for example, the AK-22, can maintain the same ammunition combat load as its predecessor with a slight increase in weight. The squad can provide overmatch capability with either a designated marksman rifle (DMR) or a GPMG.
5.45 RPL-20. By Lynndon Schooler.
GPMG and DMR
The 6.02x41 caliber suits an assault rifle and LMG’s, but for the GPMG, like the PKM, and DMRs such as the SVCh, a larger caliber would be best for greater engagement range and better armor and barrier penetration. The 6.02x41 caliber may replace the 5.45x39 caliber, while a new, larger caliber may replace the 7.62x54, possibly a revisited 6x49.
AK-308. By Lynndon Schooler.
Conclusion
The experimental 6.02x41 cartridge offers significant ballistic improvements over its predecessor and merits serious consideration for adoption along with a future weapon system to replace the AK. The recently introduced AM-17 could be chambered in this new caliber in the future. Adopting the 6mm would be part of the Russian Army's modernization effort to meet current battlefield requirements and enhance overall performance.
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