Modern Intermediate Calibers 008: The Soviet 5.45x39mm

Nathaniel F
by Nathaniel F
A 5.45x39mm 7N6 cartridge, flanked by two of its predecessors. The 5.6x39mm (left) was developed from an early Soviet ballistic test round using the 7.62x39mm case head, which was designed to duplicate the performance of the early .222 Remington Special (right), later renamed the .223 Remington.

In the late 1950s, after the first public demonstrations of the AR-15 and its new small caliber, high velocity cartridge, the Soviet Union took notice of the radical developments in military .22 caliber rounds in the United States. By 1959, four years before the adoption of the AR-15 as the M16 by the US Army, Soviet ballisticians were already testing Soviet-made replica 55gr spitzer FMJ bullets fired at over 3,000 ft/s from modified necked down 7.62x39mm cases. This program for a new small caliber high velocity lasted into the late 1960s, but it wasn’t until the mid-1970s that the 5.45x39mm caliber was eventually issued alongside the AK-74 rifle, a modified but significantly more effective variant of the previous 7.62x39mm AKM assault rifle.

Let’s get into the ballistics:

Despite its lighter bullet, the 5.45x39mm round retains its energy better than 5.56mm from comparable barrels, thanks to an excellent, carefully designed bullet shape. Even better, 5.45x39mm rounds are typically lighter, with the steel-cased 53gr 7N6 ball round weighing about 10.7 grams per shot. Despite its superior ballistics, however, the 5.45x39mm caliber has not seen the benefit of advanced antipersonnel projectile designs such as the M855A1 EPR and Mk. 318 SOST in the US, and therefore typically possesses inferior lethality. Russian armor piercing rounds such as the 7N22 and 7N24 are, however, very effective against body armor.

Note: All ballistic calculations are done with JBM’s Trajectory calculator, using the ballistic coefficient appropriate to the projectile being modeled. In this case, the calculations were done assuming an AK as the parent rifle. Also, keep in mind that there is no single true velocity for a given round; velocity can vary due to a large number of factors, including ambient temperature and chamber dimensions. Instead, I try to use nominal velocity figures that are representative of the capability of the round in question.

Nathaniel F
Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. He can be reached via email at

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  • Kivaari Kivaari on Aug 14, 2016

    Nathaniel, Are you aware at what range the 5.45mm goes so unstable as to keyhole? From match shooting it is around 930-950 yards for 7.62x51mm even with match ammo. What about with standard issue ball ammo. It strikes me that the Russian use of heavy ~174 gr. boat tail bullets originally in the Maxim machineguns prior to WW2 that they have had an advantage we voluntarily gave up. The Finns captured so much of the "long range "D" ammunition that they re-chambered their rifles to take advantage of that extended range. It seems we have done so with all our heavy loads in 5..56mm getting 69-79 gr. loads performing at quite extended ranges.

  • Spidouz Spidouz on Aug 16, 2016

    I love the look of the 7N6 bullet... even thought it's very close to the .224 and also 53gr, it's kind of weird it does look so much thinner and longer than most of .224 bullets. I would love to find some to compare them...