Soviet F1 Hand Grenade

1. Overview

The Soviet F-1 hand grenade (Russian: Фугасный 1, Fugasnyy 1 — “Explosive, Type No. 1”) is one of the most widely produced and globally proliferated anti-personnel fragmentation hand grenades in history. A defensive grenade introduced during World War II and redesigned post-war, the F-1 features a distinctive ribbed cast iron body and has been manufactured by the Soviet Union and numerous other nations across multiple continents. Nicknamed the “Limonka” (“little lemon”) for its shape and yellow-green color, the F-1 remains in widespread use today, particularly among insurgent groups and in developing-world military inventories, despite being largely superseded by more modern designs in front-line Russian service.

⚠ SAFETY WARNING: All ordnance should be considered dangerous until rendered safe by qualified EOD personnel. Unexploded ordnance should never be handled by untrained individuals. Report all suspected ordnance to military or law enforcement authorities. This information is for educational and identification training purposes only.

2. Country/Bloc of Origin

  • Country: Soviet Union (USSR)
  • Design Heritage: Based on the French F1 grenade cast iron body design
  • Period of Introduction: World War II era; subsequently redesigned post-war
  • Manufacturing Nations: Produced by the Soviet Union and under license or copy by numerous nations including China (Type 1), Bulgaria, Czech Republic, Poland, Romania, Georgia, and others
  • Current Production: Ukraine began production of an improved F-1 variant approved for military use in September 2024 during the Russo-Ukrainian War

3. Ordnance Class

  • Type: Hand grenade
  • Primary Role: Anti-personnel, defensive fragmentation
  • Delivery Method: Hand-thrown
  • Classification: Defensive — the large fragment dispersion radius (up to 200 meters) exceeds the throwing range, requiring the thrower to use cover

4. Ordnance Family / Nomenclature

  • Official Designation: F-1 (Ф-1)
  • Common Names/Nicknames:
    • Limonka (Лимонка — “little lemon,” from its shape and color)
    • Efka (Эфка — from the letter “F”)
  • Fuze Designations:
    • UZRG — wartime fuze (Universal’nyi Zapal, Ruchnaya Granata — “Universal Igniter, Hand Grenade”); 3.2–4.2 second delay
    • UZRGM — post-war modernized fuze (Modernizirovannyi — “Improved”); 3.2–4.2 second delay; also used with RG-42, RGD-5, RGO-78, and RGN-86 grenades
    • Koveshnikov fuze — alternate wartime fuze; 3.5–4.5 second delay
    • DVM-78 — more modern mousetrap fuze; 3.2–4 second delay
  • Training Variant: URG (Uchebnaya Ruchnaya Granata — “Training Hand Grenade”)
  • Related/Similar Grenades:
    • French F1 (original design ancestor)
    • American Mk 2 “Pineapple” (also modeled on the French F1)
    • Chinese Type 1 (Chinese copy)
    • MKEK Mk 2 (Turkish variant combining F-1 body with U.S. M204A2 fuze)
    • Polish F1/N60 (rifle grenade variant with impact fuze)

5. Hazards

  • Primary Hazard: Fragmentation — the cast iron body splits into approximately 290 high-velocity, sharp-edged fragments, each weighing approximately 1 gram, with an initial velocity of approximately 700 m/s (2,300 ft/s)
  • Fragmentation Behavior: Approximately 60% of the grenade body pulverizes during detonation; approximately 30% splits into the lethal fragments described above
  • Explosive Fill: 60 grams (2.1 oz) of TNT
  • Effective Casualty Radius: 20–30 meters (by various sources)
  • Fragment Dispersion Radius: Up to 200 meters — this significantly exceeds the throwing range (30–45 meters), making it a true defensive grenade requiring cover
  • Fuze Delay: 3.2–4.2 seconds (UZRGM); 3.5–4.5 seconds (Koveshnikov)
  • Critical Fuze Note: There is a persistent myth (originating from a 1983 magazine article) that UZRGM fuze variants are available with delays from zero to 13 seconds. This is incorrect — the numbers stamped on the fuze body indicate the factory production line, not the delay time. All standard UZRGM fuzes have the same delay regardless of stamped numbers.
  • UXO Considerations:
    • The F-1 is one of the most commonly encountered hand grenades in UXO and conflict zones worldwide due to its massive proliferation
    • The cast iron body resists corrosion reasonably well and can remain intact for decades
    • The TNT fill is highly stable
    • The UZRGM fuze, if separated from the grenade body, may be found as a standalone UXO hazard
    • The fuze produces an audible “pop” when initiated — this may be heard before detonation if the grenade is disturbed
    • Various production variants from different countries may have different finishes, markings, and lever/spoon designs, complicating identification
  • Environmental Degradation: The cast iron body develops surface corrosion but retains structural integrity for extended periods. The TNT fill remains hazardous essentially indefinitely under most conditions.

6. Key Identification Features

  • Shape: Egg-shaped / oval with a distinctive ribbed/notched exterior
  • Body Material: Cast iron
  • Body Dimensions: Approximately 55 mm diameter
  • Total Weight (with fuze): Approximately 600 grams (21 oz)
  • Exterior Surface: Vertically and horizontally ribbed/notched pattern — originally intended to aid fragmentation (though studies show the grooves do not significantly control fragmentation pattern) and to provide a non-slip grip
  • Color: Yellow-green (most common), dark green, or olive drab — varies by manufacturer and production period
  • Markings: Arsenal markings, lot numbers, and production codes stamped into the metal; red arsenal markings sometimes found on the base
  • Fuze Assembly: Threaded fuze well in the top of the body; the UZRGM fuze features a striker, spring-loaded safety lever (spoon), and safety pin with pull ring
  • Distinctive Features:
    • The ribbed cast iron body is the most recognizable feature
    • Strong visual similarity to the American Mk 2 “Pineapple” grenade (both derived from the French F1)
    • The UZRGM fuze is also used on multiple other Soviet grenade types

7. Fuzing Mechanisms

  • Fuze Type: UZRGM — striker-release, pyrotechnic delay
  • Arming Sequence:
    1. Remove the safety pin (straighten cotter pin ends, pull ring)
    2. Hold the safety lever (spoon) against the grenade body
    3. Throw the grenade — releasing the lever
    4. The spring-loaded striker rotates and impacts the percussion primer
    5. The primer ignites the pyrotechnic delay column
    6. An audible “pop” may be heard as the fuze ignites
  • Delay Time: 3.2–4.2 seconds (UZRGM standard)
  • Detonation: The delay column burns through to a detonator that initiates the 60g TNT main charge
  • Safety Mechanisms:
    • Safety pin with pull ring
    • Spring-loaded safety lever (spoon)
  • Fuze Interchangeability: The UZRGM is a universal Soviet fuze also used with the RG-42, RGD-5, RGO-78, and RGN-86 grenades. The UZRGM is NOT interchangeable with U.S. M200-series fuzes despite superficial similarities — the threads are incompatible.
  • Self-Destruct/Self-Neutralization: None

8. History of Development and Use

The Soviet F-1 was introduced during World War II as a standardized defensive fragmentation grenade for the Red Army. Its design drew directly from the French F1 grenade body, which had been widely used by Imperial Russia and later the Bolshevik forces during the Russian Civil War. The Soviet Union modified the design and paired it with domestically developed fuzes (initially the UZRG, later the modernized UZRGM).

During World War II, the F-1 was mass-produced in enormous quantities and became one of the primary infantry weapons of the Red Army. It was used across the entire Eastern Front, from the defense of Moscow and the siege of Stalingrad to the final assault on Berlin. Its simple, robust design was well-suited to the Soviet industrial base, which prioritized mass production of reliable, uncomplicated weapons.

Post-war, the F-1 was redesigned and the UZRGM fuze was standardized, providing improved reliability. The grenade was exported extensively throughout the Cold War to Soviet allies, client states, and liberation movements across Africa, Asia, the Middle East, and Latin America. Manufacturing licenses were granted to numerous Warsaw Pact and aligned nations.

The F-1 was also widely copied. China produced it as the Type 1 Grenade, and numerous other countries produced their own variants with minor modifications. The grenade appeared in virtually every major conflict of the Cold War era, from Korea and Vietnam to the Arab-Israeli wars, the Soviet-Afghan War, and countless civil conflicts.

While no longer regarded as a front-line weapon by Russia and former Warsaw Pact nations (having been supplemented by the RGD-5, RGO, and RGN series), the F-1 remains in widespread use globally, particularly among insurgent and non-state armed groups. During the ongoing Russo-Ukrainian War, Ukraine approved production of an improved F-1 variant in September 2024.

9. Technical Specifications

ParameterValue
ShapeEgg-shaped / oval, ribbed
Body MaterialCast iron
Body Diameter~55 mm
Total Weight (with fuze)~600 g (21 oz)
Explosive FillTNT
Fill Weight60 g (2.1 oz)
FuzeUZRGM (standard post-war)
Fuze Delay3.2–4.2 seconds
Fragments Produced~290 (from ~30% of body mass)
Fragment Weight~1 g each
Fragment Initial Velocity~700 m/s (2,300 ft/s)
Effective Casualty Radius20–30 m
Fragment Dispersion RadiusUp to 200 m
Throwing Range30–45 m

10. Frequently Asked Questions

Q: Is the myth about variable-delay UZRGM fuzes (0–13 seconds) true? A: No. This is a persistent myth originating from a 1983 magazine article that misidentified the numbers stamped on the UZRGM fuze body as delay indicators. These numbers actually indicate the factory production line number. All standard UZRGM fuzes have the same 3.2–4.2 second delay regardless of the numbers stamped on them. The stamped numbers are concealed when the fuze is inserted into the grenade body.

Q: Can the UZRGM fuze be used in U.S. grenades (or vice versa)? A: No. Despite superficial similarities in appearance, the UZRGM fuze threads are incompatible with U.S. grenade fuze wells (M200 series). The UZRGM can only be screwed approximately halfway into a U.S. grenade, resulting in an insecure and dangerous condition. Similarly, U.S. fuzes will not properly seat in Soviet grenade bodies.

Q: Why is the F-1 classified as a “defensive” grenade? A: The F-1’s fragment dispersion radius (up to 200 meters) significantly exceeds its throwing range (30–45 meters). This means that a soldier who throws an F-1 without taking cover behind a wall, in a trench, or behind another solid barrier risks being struck by fragments from their own grenade. This characteristic defines it as a defensive grenade — it should only be used from a protected position.

Q: How does the F-1 compare to the American M67? A: Both are defensive fragmentation grenades, but they differ in design philosophy. The M67 uses a pre-formed fragmentation coil inside a smooth steel body for a more controlled fragment pattern, weighs 400 grams with Composition B fill (180g), and has a 5-second fuze delay. The F-1 uses its cast iron body as the fragmentation source (less controlled pattern), weighs 600 grams with a smaller TNT charge (60g), and has a 3.2–4.2 second delay. The F-1 is heavier but relies on its massive iron body for fragmentation effect rather than a large explosive charge.

Q: What does the ribbed/grooved pattern on the body actually do? A: The grooves were originally intended to create predictable fragmentation lines, causing the body to break along the grooves into uniform fragments. However, studies have shown that the grooves do not significantly control the fragmentation pattern — approximately 60% of the body pulverizes regardless of the grooves. The grooves do serve a practical purpose as a non-slip grip surface, particularly in wet or cold conditions.

Q: Why is the F-1 still so commonly encountered worldwide? A: The combination of massive production quantities, extensive Cold War-era export to dozens of nations, licensed manufacturing in multiple countries, the grenade’s extreme simplicity and durability, and the long shelf life of its TNT fill means that F-1 grenades produced decades ago remain functional and available in conflict zones worldwide. Its proliferation is comparable to the AK-47 rifle in terms of global reach.

Q: How can different production origins of the F-1 be identified? A: F-1 grenades from different manufacturing nations vary in their finish (paint color and texture), casting quality, fuze well dimensions, safety lever (spoon) design, and markings. Soviet-produced examples typically feature a yellow-green finish with Cyrillic stampings. Other producers may use different color schemes and marking conventions. The fuze type (UZRGM variant, DVM-78, or other) can also indicate origin.

Q: What production variant did Ukraine develop during the Russo-Ukrainian War? A: Ukraine approved production of an improved F-1 variant for military use in September 2024. This reflects the practical reality that the F-1 body design is simple to manufacture, and the UZRGM fuze platform is well-understood. The specific improvements in the Ukrainian variant have not been fully detailed in open sources at the time of this lesson’s preparation.