115 mm APFSDS-T 3UBM-5 round

cap covering the blunt front end of the penetrator while a six-finned assembly, also made of steel and with a maximum diameter over the forward-folding fins of 115.06 mm, is threaded on at the rear. A T-20-1 tracer element is carried in the rear of the fin assembly. A variant with an armour-piercing cap over a more pointed penetrator nose is known to exist; it is 549.66 mm long in total and the projectile with sabot weighs 5.4 kg. The rimmed brass cartridge case has an unusual shape as it is necked approximately halfway along its length. It is filled with 6 kg of 12/7 and 18/1 Tr propellant in stick and granular form. The base is fitted with a KV-5-U electrical primer which has a long flash tube. The 3BM-6 APFSDS-T has a muzzle velocity of 1,680 m/s and its maximum effective range is 3,000 m, although most accounts of effective combat range mention 1,500 m. Maximum possible range is 12,230 m. The projectile can penetrate up to 228 mm of armour set at 0º at 1,000 m or 199 mm of armour set at 60º at the same range. The 115 mm U-5TS (2A20) smoothbore tank gun was developed during the latter half of the 1950s and entered service in the early 1960s, mounted on the T-62 tank series. The T-62 therefore became the first in-service main battle tank to feature an APFSDS round, the 3BM-3, in its armoury. The later 3BM-6, often referred to as an HVAPFSDS-T, became the standard APFSDS-T projectile on the 3UBM-5 round for the U-5TS gun tanks. There are now few references to the earlier 3BM-3.