Talyn
SAINT
The 5.45x39mm Russian |
The 5.45×39mm cartridge is a rimless bottlenecked intermediate cartridge. It was introduced into service in 1974 by the Soviet Union for use with the new AK-74. The 5.45×39mm gradually supplemented, then largely replaced the 7.62×39mm cartridge in Soviet and Warsaw Pact service as the primary military service rifle cartridge. The 5.45×39mm cartridge was developed in the early 1970s by a group of Soviet designers and engineers under the direction of M. Sabelnikov. Further group members were: L. I. Bulavsky, B. B. Semin, M. E. Fedorov, P. F. Sazonov, V. Volkov, V. A. Nikolaev, E. E. Zimin and P. S. Korolev. The 5.45×39mm couples a sensible case volume to bore area ratio with ample space for loading relatively long slender projectiles that can provide good aerodynamic efficiency and external ballistic performance for the projectile diameter. The 5.45×39mm is an example of an international tendency towards relatively small-sized, lightweight, high-velocity military service cartridges. Cartridges like the 5.45×39mm, 5.56×45mm NATO and Chinese 5.8×42mm allow a soldier to carry more ammunition for the same weight compared to their larger and heavier predecessor cartridges, have favourable maximum point-blank range or "battle zero" characteristics and produce relatively low bolt thrust and free recoil impulse, favouring lightweight arms design and automatic fire accuracy. Early ballistics tests demonstrated a pronounced tumbling effect with high speed cameras. Some Western authorities believed this bullet was designed to tumble in flesh to increase wounding potential. At the time, it was believed that yawing and cavitation of projectiles were primarily responsible for tissue damage. Martin Fackler conducted a study with an AK-74 assault rifle using live pigs and ballistic gelatin; "The result of our preset test indicate that the AK-74 bullet acts in the manner expected of a full-metal-cased military ammunition—it does not expand or fragment when striking soft tissues". Most organs and tissue were too flexible to be severely damaged by the temporary cavity effect caused by yaw and cavitation of a projectile.[8] With the 5.45 mm bullet, tumbling produced a temporary cavity twice, at depths of 3.9 in and 13.8 in. This is similar to (but more rapid than) modern 7.62×39mm ammunition and to (non-fragmenting) 5.56 mm ammunition. Military 5.45×39mm rounds offer better penetration over (fragmenting) military 5.56×45mm NATO rounds. Non-fragmenting or full metal jacket 5.56x45mm NATO rounds offer better penetration of armor than 7N6M 5.45x39mm bullets, but lower than 7N10 bullets. The 5.45×39mm was developed by the Soviet Union for military use and it was not intended to create civilian weapons in this chambering. When 5.45×39mm ammunition finally became available for sale to civilians, several arms manufacturers started to offer semi-automatic AK-74 variants in the calibre for civilian use. Sometimes these weapons combine parts originating from Russia or Eastern European states and parts produced elsewhere. Only a few civilian 5.45×39mm weapons were developed and commercially offered. Non-AK-74 rifles and commercial offerings include the East German Ssg 82 bolt action rifle and the Russian CRS-98 "Vepr-5, 45" semi-automatic carbine and Saiga semi-automatic rifle. In May 2008 the Smith & Wesson M&P15R was introduced. This was a standard AR-15 rifle chambered for the 5.45×39mm cartridge and was Smith & Wesson's first AR-variant rifle in a chambering other than 5.56×45mm NATO and is no longer in current (2012) production. The civilian version of the Tavor TAR-21 rifle produced for the US market includes an optional 5.45×39mm conversion kit. |
