A heavier round, weighing in at 182gr and having a boat tailed bullet to increase flight stability, was also introduced in 1930. Rather than being called "T" for tyazhelaya ("heavy"), as one would expect, it was styled "D", for dal'noboinaya ("long-range"); the reason for this inconsistency of nomenclature goes unremarked and unexplained in the sources (Shipp, "Red Army Infantry Weapons, Tanks, and Armored Cars", based on an intelligence study prepared for the Estonian General Staff and presented in 1933)
Virtually all Finnish Mosin-Nagants will have a capital "D" stamped on their chambers (generally on the buttstock as well) to indicate that they have been chambered for the Finnish D166 cartridge, which was developed to take advantage of the huge amount of captured Soviet "D" ammunition.
As the Estonian intelligence study which was the primary source noted, the "D" round was preferable for use at ranges exceeding 1000 meters because, even though it had a lesser muzzle velocity, due to its shape and greater cross-section load it maintained its velocity longer and "produces casualties even at the maximum range (1500 meters) when its final velocity is 140m/s (the bullet can still penetrate a man at velocity 116m/s).")
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With military equipment of every sort from long underwear to weapons-grade plutonium hemmorrhaging from the former East Bloc, we should not be surprised to find ammunition for the 7.62mm ShKAS (Shpitalniy-Komaritskii Rapid-Fire Aviation Machine-gun) surfacing now and then. While it can be fired in Mosin-Nagant rifles and carbines, it is not wise to do so as it can cause damage, principally to the interrupter-ejector. These rounds are easily identified by the red-enameled foil covering the primer on the bottom of the cartridge case and the Cyrillic letter Ш next to it.
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(table)
Bullet, red tip, type Ranging-Incendiary (PZ) (may be erroneously called ZP on occasion), 142gr
Warning: The PZ round was designed for use in machineguns: attempting to fire it from rifles or carbines is exceedingly dangerous and should be strictly avoided. This round is unstable, having a striker device and an explosive vial or capsule in the bullet's center; it as been known to explode at highly inconvenient times for the shooter.
