5.66 x 39 MPS cartridges near Kiev

N.R. Jenzen-Jones

The seizure of former president Viktor Yanukovych’s estate in Mezhyhirya, an hour’s drive from Kiev, turned up a range of interesting arms and munitions. Nearby, a variety of ammunition was recovered from a private lake, including the cartridges shown in the image above. These are 5.66 x 39 mm rounds for the Russian made APS (Автомат Подводный Специальный) underwater “assault rifle”, which are available in three types. Two are designated as the MPS (МПС; морской патрон специальный) and MPST (МПСТ; морской патрон специальный трассирующий). The final is a training cartridge of unknown designation. Whilst the APS is commonly referred to as an assault rifle, the barrel of the Avtomat Podvodny Spetsialny or “special underwater assault rifle” is not actually rifled, and the projectiles are stabilised by hydrodynamic effects. 

The MPS (Morskoy Patron Spetsialnyy; “special marine cartridge”) and  MPST (Morskoy Patron Spetsialnyy Trassiruyushchiy; “special marine tracer cartridge”) cartridges feature long, slender dart-like projectiles of a nominal 120 mm length. The projectiles are of lacquered steel, with the MPST projectile featuring a tracer canister at its base. The lacquered steel cartridge cases are sealed at the case mouth and the primer annulus to prevent the ingress of moisture. The cartridges above appear to be MPS rounds. 

Ukrainian military frogmen are known to use the APS rifle and associated MPS/MPST ammunition. Sources in Ukraine have also indicated that the presidential security detail also had frogmen on the team, and it seems likely that the ammunition documented belonged to that unit.

Whilst there is little public domain information on these cartridges, the following specifications (for the MPS cartridge) and diagrams are taken from the Russian language book Ammunition For Small Arms, by  L.V. Kolomiytsev, V.T. Nikitiuk,  I.S. Sobakar, and  V.V. Somov, published in Ukraine in 2003. 

МПС (MPS) Cartridge Specifications 
Calibre: 5.66 x 39
Cartridge length: 149.6 – 150.0 mm
Cartridge weight: 27.5 – 28.0 g
Muzzle velocity when fired from APS above water: 350 – 365 m/s
Muzzle energy when fired from APS above water: 1237.3 – 1365.6 J

Propellant
Propellant type: smokeless pyroxyline
Weight of powder charge: 1.40 – 1.42 g
The maximum pressure of the powder gases: 295.9 MPa

Projectile
Lacquered steel projectile
Bullet weight: 20.2 – 20.5 g
Bullet length:  119.8 – 120.0 mm

Cartridge case
Weight of cartridge case with primer: 5.50 – 5.57 g
Cartridge case length: 39.5 – 39.7 mm
Material: lacquered steel
МПС & МПСT
The following is an extract from a TSNIITOCHMASH flyer advertising the APS rifle for export. Note the inset image showing MPS (left) and MPST (right) cartridges. 

APS_flyer

With thanks to Yuri Lyamin and Ivan Kochin.