85 mm O-365K high-explosive round

Also known as

O-365K
UO-365K
53-O-365K
53-UO-365K

The O-365K is the projectile in the Soviet 53-UO-365K fixed 85 mm high-explosive fragmentation round, used with the 53-O-365K projectile, fuze, and 365-series charge components. It belongs to the shared 85 mm ammunition family for D-44 divisional guns and wartime Soviet 85 mm tank or self-propelled guns, with sources emphasizing fragmentation effects against personnel, equipment, and light fortifications rather than a large demolition charge.

85 mm O-365K high-explosive round, 85 mm HE-fragmentation round, Munitions

Image source: On The Way Models RB_P04 Review

Profile / Specs

Profile

Origin: Soviet Union
Built by: Soviet
Type: 85 mm HE-fragmentation round

Specifications

Caliber: 85 mm
Configuration: Fixed (unitary) HE-frag round
Complete round mass: About 15.1-16.3 kg in open 85 mm ammunition tables
Projectile mass: 9.54 kg
Explosive filler: TNT filler; open tables list about 0.646-0.741 kg for O-365K-family rows
Fuze: KTM-1 family; METIS also lists MG-N, KTM-1-U, KTMZ-1, and KTMZ-1-U
Case: Steel-cased projectile in a fixed round
Ballistic context: D-44 ballistic tables include O-365K and O-367A high-explosive data
Intended effect: Fragmentation against personnel, equipment, aerial targets, and light field fortifications

Variants

Adjacent 365-series 85 mm fragmentation rounds and suffixes changed fuzes, projectile construction, or driving-band material while staying in the same Soviet 85 mm ammunition family.

Variant	Configuration	Designation notes
UO-365 / O-365	Earlier 85 mm HE cartridge/projectile	Battlefield.ru lists O-365 with a T-5 fuze and lighter projectile than O-365K, while Tank Archives says O-365 with a T-5 time fuze remained usable for target indication, signals, and personnel effects. Sources: Battlefield.ru: 85mm S-18 Tank Gun, Tank Archives: 85 mm for Dummies
UO-365KV	Fuze suffix variant	Battlefield.ru lists UO-365KV/O-365KV with V-429 and KTM-family fuze options, and Tankograd explains the V suffix as the V-429-fuzed cartridge form. Sources: Battlefield.ru: 85mm S-18 Tank Gun, Tankograd: Soviet Towed Anti-Tank Guns
UO-365KZh	Driving-band variant	Tankograd describes UO-365KZh as a wartime variant that replaced normal driving bands with iron-ceramic bands while retaining the same case and explosive filler. Sources: Tankograd: Soviet Towed Anti-Tank Guns
85 mm O-367A high-explosive round	Adjacent 85 mm HE-fragmentation round	Battlefield.ru lists O-367A in the same 85 mm HE-fragmentation ammunition table with KTM-1-U, KTM-1, and MG-N fuze options, and the linked catalog record covers that adjacent projectile. Sources: Battlefield.ru: 85mm S-18 Tank Gun

Firing Weapons

Tank Archives ties the round to the Soviet 85 mm gun family and lists it in the D-44's ballistic tables.

Firing weapon	Weapon type	Firing evidence
D-44	85 mm divisional gun	Tank Archives' D-44 ballistic tables include O-365K HE data for the gun. Sources: Tank Archives: D-44 Ballistic Tables
T-34/85 Tank	85 mm-gun medium tank	WW2 Equipment Data lists UO-365K as fired from the M1943 D-5T85 and M1944 ZiS-S53 tank guns, while The Tank Museum identifies the T-34/85 main weapon as an 85 mm ZiS-53 gun. Sources: WW2 Equipment Data Soviet Explosive Ordnance - 85mm and 100mm Projectiles, T-34/85 Tank Collection Page

Firing weapon

Weapon type

Firing evidence

D-44

85 mm divisional gun

Tank Archives' D-44 ballistic tables include O-365K HE data for the gun.

Sources: Tank Archives: D-44 Ballistic Tables

T-34/85 Tank

85 mm-gun medium tank

WW2 Equipment Data lists UO-365K as fired from the M1943 D-5T85 and M1944 ZiS-S53 tank guns, while The Tank Museum identifies the T-34/85 main weapon as an 85 mm ZiS-53 gun.

Sources: WW2 Equipment Data Soviet Explosive Ordnance - 85mm and 100mm Projectiles, T-34/85 Tank Collection Page

Designation And Ammunition Context

The O-365K page is best read as a projectile-and-cartridge family record rather than a standalone battlefield system. The complete round, projectile, and fuze suffixes appear under different labels in open references.

Complete round

53-UO-365K / UO-365K is the fixed 85 mm HE-fragmentation round.

METIS describes the complete round as a unitary cartridge assembled with projectile, fuze, and charge components.

Projectile

53-O-365K / O-365K is the spin-stabilized fragmentation projectile inside the round.

Bulletpicker and METIS both separate the projectile identity from the complete-round designation.

Gun family

Sources tie the round to the 85 mm D-44 and to D-5T85/ZiS-S53 tank-gun ammunition.

This relationship-only page does not add conflict-use rows without direct sources naming the round in a specific conflict.

Source labels used here: METIS: 53-UO-365K Projectile; Bulletpicker: Projectile, 85mm Frag, O-365K; Battlefield.ru: 85mm S-18 Tank Gun; Tankograd: Soviet Towed Anti-Tank Guns; Tank Archives: D-44 Ballistic Tables; WW2 Equipment Data Soviet Explosive Ordnance - 85mm and 100mm Projectiles.

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