Russian BK-14M 125mm HEAT-FS Projectile

1. Overview

The BK-14M (3BK14M in full GRAU nomenclature) is a Soviet/Russian 125mm High-Explosive Anti-Tank, Fin-Stabilized (HEAT-FS) projectile designed for the 2A46 series smoothbore tank guns. It is a separate-loaded, fin-stabilized projectile incorporating a shaped-charge warhead with a copper liner, capable of penetrating 450mm of rolled homogeneous armor (RHA) at 0 degrees. The BK-14M is fired from the main guns of the T-64, T-72, T-80, T-90, and other tanks derived from these designs. It has been documented in active use during the Russia-Ukraine conflict (2022–present).

Note: The user’s original request listed this item as an “HE Projectile.” The BK-14M is correctly classified as a HEAT-FS (High-Explosive Anti-Tank, Fin-Stabilized) projectile — a shaped-charge anti-armor munition, not a conventional high-explosive fragmentation round.

2. Country/Bloc of Origin

  • Country of Origin: Soviet Union (USSR) / Russian Federation
  • Development Period: 1960s–1970s; the BK-14M with copper liner entered service circa 1975
  • The BK-14M is the improved version of the BK-14, replacing the original steel shaped-charge liner with a copper liner for improved penetration performance
  • Widely distributed to all nations operating Soviet/Russian T-series main battle tanks

3. Ordnance Class

  • Type: Tank gun projectile (anti-armor, shaped charge)
  • Primary Role: Defeat of armored vehicles, particularly lighter or older tanks and armored personnel carriers
  • Delivery Method: Fired from 125mm smoothbore tank guns (2A46 series, designated D-81 in some references)
  • Classification: Separate-loading, fin-stabilized, HEAT (shaped charge) projectile with tracer

4. Ordnance Family / Nomenclature

  • Projectile Designation: BK-14M (3BK14M in full GRAU nomenclature; “3БК14М” in Cyrillic)
  • Complete Round Designation: 3VBK-10M (complete cartridge: projectile + propellant charge)
  • Propellant Charge: 4Zh40 (4Ж40) — combustible cartridge case with steel base stub
  • Caliber: 125mm
  • Related Variants:
    • BK-12 (3BK12) — earlier HEAT projectile with steel cone and I-238 electromechanical impact fuze
    • BK-12M (3BK12M) — BK-12 with copper cone
    • BK-14 (3BK14) — improved HEAT with steel cone and piezoelectric fuzing (PIBD)
    • BK-14M (3BK14M) — BK-14 with copper cone (the subject of this lesson)
    • BK-18 / BK-18M — later generation HEAT projectiles with further improvements
    • BK-29 / BK-29M — modern improved HEAT variants
  • Note on Nomenclature: Full GRAU designations do not contain hyphens (e.g., 3BK14M, not 3BK-14M). The hyphenated form is a common Western convention.

5. Hazards

  • Primary Hazards:
    • Shaped-Charge Jet: Upon detonation, the copper-lined shaped charge produces a hypervelocity metal jet capable of penetrating 450mm of steel armor
    • Blast: Significant blast effect from the HE charge (1.62 kg of explosive)
    • Fragmentation: Steel body and fin assembly produce fragmentation upon detonation
  • Explosive Fill: Approximately 1.62 kg of Okfol (a composition of 75% HMX and 25% TNT), or A-IX-1 in some production variants
  • Fuze Sensitivity: The BK-14M uses a piezoelectric point-initiating, base-detonating (PIBD) fuze system that is sensitive to impact. The fuze arms through setback during firing
  • UXO Considerations:
    • Unexploded HEAT projectiles retain their full shaped-charge penetration capability
    • The piezoelectric fuze is impact-sensitive and may function upon minimal disturbance
    • The setback-armed fuze mechanism means a fired but unfuzed round may still be in a partially armed state
    • The fins, which deploy after leaving the barrel, may indicate whether the round has been fired
    • Combustible cartridge case components may make it harder to determine if the round is a complete unfired cartridge or a fired projectile
  • Kill Radius: The primary anti-armor effect is directional (shaped-charge jet), but blast and fragmentation effects are dangerous to personnel within a substantial radius

⚠ WARNING: All ordnance should be considered dangerous until rendered safe by qualified EOD personnel. HEAT projectiles with piezoelectric fuzing are impact-sensitive and extremely hazardous. Never approach, handle, or attempt to move suspected ordnance.

6. Key Identification Features

  • Caliber: 125mm
  • Projectile Weight: 19 kg
  • Projectile Length: 675–680mm
  • Complete Cartridge Length: 1,084mm (projectile placed on cartridge case)
  • Shape: Distinctive HEAT projectile profile with:
    • Pointed nose section housing the piezoelectric element
    • Cylindrical body
    • Tailpiece with six spring-loaded fins that deploy after leaving the barrel
  • Fin Tailplane Span: 343mm (when deployed)
  • Color and Markings:
    • Markings stenciled on the projectile body include nomenclature (BK-14M), manufacturing information, and explosive fill type
    • Specific color may vary by production lot
  • Distinctive Features:
    • Six deployable fins on the tail section (spring-loaded, held in place by a setback ring during storage and firing)
    • Pointed nose with piezoelectric sensing element
    • No rotating band — the projectile is fin-stabilized for a smoothbore gun
    • Combustible cartridge case with a steel base stub (4Zh40) — only the short steel base is ejected after firing
  • Material: Steel body, copper shaped-charge liner

7. Fuzing Mechanisms

  • Fuze Type: V-15 (or suitable equivalent) — Point-Initiating, Base-Detonating (PIBD) fuze with piezoelectric initiation
  • System Description: The BK-14M uses a closed-circuit electrical fuzing system with fully insulated inner components housed within the projectile body
  • Arming Sequence:
    1. Transport Safety: A spring-loaded inertia pin moves rearward under setback during firing, releasing the first locking ball from a V-groove in the slider, allowing partial movement
    2. Firing Safety: A second setback-activated inertia pin fixes the slider during acceleration. After the projectile exits the barrel and acceleration decreases, the spring pushes the inertia weight forward, releasing the second ball and allowing the slider to move the electric firing cap under the detonator
    3. Distant Arming: The fuze completes arming between 2.5m and 40m from the muzzle
  • Functioning:
    • Upon impact, the piezoelectric element in the nose generates an electrical current
    • This current ignites the electric detonator via the now-aligned firing cap
    • The detonator initiates the booster charge, which detonates the main shaped-charge explosive fill
    • The detonation collapses the copper cone into a hypervelocity penetrating jet
  • Key Difference from Earlier BK-12: The BK-12/BK-12M used the I-238 electromechanical impact fuze with a “spitback” detonator that ignited the base detonator via a flame path. The BK-14M’s closed-circuit piezoelectric system is more reliable and resistant to electromagnetic interference

8. History of Development and Use

  • Development: The 125mm smoothbore tank gun ammunition family was developed beginning in the early 1960s by the Soviet Union to counter evolving NATO armor capabilities. The first 125mm HEAT round (BK-12) entered service in 1962 with the T-64 tank
  • Evolution:
    • BK-12 (1962): First-generation HEAT with steel cone and electromechanical fuze
    • BK-12M (1968): Replaced steel liner with copper for improved penetration (~10% improvement)
    • BK-14 (1968): Introduced piezoelectric PIBD fuzing and improved design
    • BK-14M (~1975): Introduced copper liner and wave-shaping booster for optimized jet formation
  • Service Platforms: T-64, T-72, T-80, M-84, T-90, PT-91, and derivative tanks equipped with the 2A46 series smoothbore gun; also the 2A45 Sprut anti-tank gun
  • Combat Use: HEAT rounds in the 125mm family have seen combat in:
    • Soviet-Afghan War (1979–1989)
    • Iran-Iraq War (1980–1988)
    • Gulf War (1990–1991)
    • Chechen Wars (1994–2009)
    • Various Middle Eastern and African conflicts
    • Russia-Ukraine conflict (2022–present)
  • Current Status: The BK-14M remains in active service with Russian and numerous other armed forces. While newer HEAT variants exist (BK-18M, BK-29M), the BK-14M continues to be a widely held inventory item
  • Limitations: HEAT rounds have been increasingly supplemented by APFSDS rounds for anti-armor work, as modern composite and reactive armor significantly degrades shaped-charge effectiveness. HEAT rounds remain useful against lighter vehicles, fortifications, and older armor

9. Technical Specifications

ParameterSpecification
Caliber125mm
Projectile Weight19 kg
Projectile Length675–680mm
Complete Cartridge Length1,084mm
Projectile TypeHEAT-FS (with tracer)
Explosive FillOkfol (75% HMX / 25% TNT) or A-IX-1
Explosive Weight1.62–1.76 kg
Shaped-Charge ConeCopper
Armor Penetration450mm RHA at 0°
Muzzle Velocity905 m/s
FuzeV-15 PIBD (piezoelectric)
Distant Arming2.5–40m
Fin Span343mm
Propellant Charge4Zh40 (5 kg propellant)
Cartridge Case Weight10 kg (with propellant)
Max Chamber Pressure300 MPa
Compatible Weapons2A46 series (D-81) 125mm smoothbore guns
PrimerGUV-7 (or suitable equivalent)

10. Frequently Asked Questions

Q: What is the difference between the BK-14 and BK-14M? A: The BK-14 uses a steel shaped-charge liner, while the BK-14M uses a copper liner. Copper produces a more coherent, higher-velocity jet upon detonation, resulting in approximately 10% greater armor penetration. The “M” suffix stands for “медь” (med’), the Russian word for copper. Both use the same piezoelectric PIBD fuzing system.

Q: How does the combustible cartridge case work in 125mm tank ammunition? A: The 125mm ammunition uses a two-piece loading system designed for autoloader compatibility. The propellant charge is housed in a combustible cylinder glued to a short steel base stub. During firing, the combustible portion burns completely, and only the short steel base stub is ejected from the breech. This reduces the volume of waste in the fighting compartment. However, a disadvantage is that unfired cartridges stored in the tank are exposed, and a penetrating hit can cause catastrophic ammunition detonation.

Q: Why has the BK-14M not been fully replaced by newer HEAT variants? A: While newer designs like the BK-18M and BK-29M offer improved performance, the BK-14M remains in service due to massive existing stockpiles, proven reliability, and the fact that it remains effective against a wide range of targets including older tanks, APCs, fortifications, and light vehicles. Modern armies typically maintain a mix of ammunition types, with APFSDS rounds preferred for engaging modern armor and HEAT rounds retained for other targets.

Q: What makes the piezoelectric fuze system significant for EOD considerations? A: The piezoelectric fuze generates an electrical current upon mechanical impact — it requires no battery or external power source. This means an unexploded BK-14M retains its fuzing capability indefinitely without degradation from battery depletion. The fuze is inherently impact-sensitive once armed, making unexploded rounds extremely dangerous to approach or disturb. The dual-safety arming mechanism (setback-activated) means a fired round that failed to function may be fully armed and awaiting only an impact to detonate.

Q: How can a BK-14M be distinguished from other 125mm projectiles in the field? A: Key features include the pointed nose (housing the piezoelectric element), the cylindrical body profile characteristic of HEAT rounds, and the six deployable tail fins. APFSDS rounds are visually very different with their long, thin dart penetrators and discarding sabot petals. HE-Frag rounds (like the 3OF26) have a more conventional ogive shape and different fuze arrangements. The BK-14M’s tail section with its fin deployment mechanism is its most distinctive external feature.

Q: What is the significance of the catastrophic turret ejection phenomenon associated with T-72 tanks? A: The 125mm ammunition (including BK-14M rounds) is stored relatively exposed in the T-72’s carousel autoloader within the fighting compartment. A penetrating hit can ignite the propellant charges and detonate the warheads, causing a catastrophic explosion that typically blows the turret completely off the hull. This vulnerability has been extensively documented in conflicts from the Gulf War through the Russia-Ukraine conflict and is a well-known characteristic of tanks using this ammunition storage configuration.