nonsubmersible

United States hand grenades

The military of the United States has used dozens of different types of hand grenades since its foundation. Presented on this page is a basic overview.

High Explosive; Fragmentation and Blast

Mk II and Mk IIA1

More commonly known as the "Pineapple" the Mk II series (also written Mk 2) was the most common US fragmentation grenade of the Second World War. The Mk II body featured a serrated exterior designed to aid grip in poor condition. A common misconception is that the grooves aid fragmentation of the grenade; studies have disproved this. The filling is either TNT (approx 2 ounces), or EC blank fire powder (approx ¾ of an ounce smokeless small arms powder).

The Mk II was also available in a little-known HE-Blast (better known as "concussion") variant and a combined effect HE-Frag variant. This was largely superseded by the Mk III series. The Mk IIA1 (also written Mk 2A1) used the M10A2 or M10A3 fuzes, upgrades to the previous M10A1 fuze used in the Mk II. Later reissued Mk II variants featured the modern M204 series fuze.

Mk III, Mk IIIA1, and Mk IIIA2

Unlike the Mk II, the Mk III (also written Mk 3) was a cylindrical grenade designed to be used as an "offensive" weapon for clearing rooms, trenches, and other enclosed spaces. A concussion grenade, the Mk III series was designed to incapacitate through the pressure and impulse produced by the explosive fillings detonation. The MkIII had a far larger TNT filling than the Mk II series; up to 8 ounces of TNT, in comparison to 1.8 ounces. Although a minimum fragmentation grenade, large fragments (most likely the fuze assembly, or surrounding material) could be projected as far as 200 m from the detonation point. The differences between the Mk III, the Mk IIIA1 (also written Mk 3A1) and the Mk IIIA2 (also written Mk 3A2) was the continual improvement of the M6 fuze. The Mk III featured the M6/A1, the Mk IIIA1 the M6A2, and the Mk IIIA2, the M6A3. Later reissued Mk III variants featured the modern M206 series fuze.

M26/A1/A2, M57 and M61

The M26 series is in many ways an upgrade in basic principle of the Mk II. A similarly shaped, but not visibly ribbed fragmentation grenade. The M26 has a filling of Composition B contained within a sheet steel two part outer shell which covers a prenotched fragmentation coil inner liner. The use of the inner liner creates a highly predictable fragment pattern and causality radius. The grenade was found to have problems with complete detonation of the filler, and the M26A1 featured a tetryl booster to ensure complete detonation. The M61 was the product of a further Product Improvement Project or PIP, and is identical to the M26A1 with the exception of the additional safety clip for the spoon of the grenade on the M61. The M26A2 is identical to the M26A1 except for being fitted with the M217 impact fuze. The M57 is the equivalent of the M61 for the M26A1, and is the same as the M26A2 with the exception of the additional safety clip on the spoon of the grenade.

M33, M33A1/M59, M67, and M68

Similar in format to the M26, the M33 is a spherical fragmentation grenade also filled with Composition B explosive. Unlike the M26, the inner wall is prescored and does not contain a fragmentation coil. The grenade's exterior has smooth appearance, compared to the Mk II series pineapple appearance. The M67 was part of a similar PIP, and is identical to the M33 with the exception of the additional safety clip for the spoon of the grenade on the M67. Early M33 grenades were also more of an oval shape before transitioning over to the more spherical shape of the M67. The M67 is the current issue HE-Frag grenade for the US military. The M33A1 is the impact version of the M33, using the M217 electrical impact fuze in place of the normal delay fuze. At an unknown point the M33A1 was redesignated as the M59. There should be no difference between these grenades with the possible exception of the M33A1 being more ovular in shape, while the M59 might appear more spherical. The M68 is the same as the M59, with the exception of the additional safety clip.

Mk 40 Mod 0/1

The Mk 40 is a TNT filled concussion grenade specifically for use against enemy divers and frogmen. The grenade is designed to be employed essentially as an anti-personnel depth charge, killing or otherwise incapacitating the target by creating a lethal shockwave underwater, similar to that of a full-size depth charge.

Smoke and Signaling Grenades

M1 "Frangible" FS

The United States standardized a common pint bottle "Molotov Cocktail" style "grenade" in 1942. It had a number of fillers, including a sulphur trioxide chlorsulfonic acid mixture, also known as FS, a corrosive chemical mix that created a heavy smoke when exposed to air. This grenade required no fuze. The main purpose was anti-vehicle; the grenade would be smashed on a tank's air intake, filling the crew compartment with smoke.

M8, M83 and Model 308-1 White Smoke

A smoke grenade similar visually to the Mk III HE-Blast grenade, the M8 (also written AN/M8) is filled with hexachloroethane or HC for short, a chemical agent that produces a thick white smoke when burned. The M8 is used for signaling and screening purposes, and since it works by burning the HC for its effect, it can also be used as an improvised incendiary device. HC smoke is toxic and can cause more serious health problems with prolonged exposure. The M83 (also written AN/M83) is a modernized version of the M8, using TA instead of HC as the filler mixture. The Model 308-1 White Smoke was a modified version of the M8 produced at the Special Operations Branch of the Naval Weapons Center at China Lake California, often simply referred to as China Lake. The Model 308-1 was modified for a US Navy SEAL requirement with a greater burning rate, meaning a greater smoke output but a shorter overall burning time.

M15, M16, and M34

The M15 is a white phosphorus smoke grenade, nicknamed Willie Peter or Willie Pete (White Phosphorus), used for screening and signaling purposes. It is cylindrical, but with rounded edges compared to the those of the M8. WP has many of the same properties of HC, and is also burned to create the effect, giving the M15 a similar incendiary capability. The M16 was a version of the grenade, featuring a number of colors. The M16 was originally available in: blue, green, orange, red, violet, yellow, black and blue. This was later reduced only to the following four colors: red, yellow, green, violet. The M34 was a variant of the M15 designed to be able to be used as a rifle grenade using the M2 series of grenade launching adapters, and was ribbed to give the fins better grip on the grenade body.

M18

A purpose designed "smoke flare," the M18 was a smoke grenade visually similar to the M8, but with a different type of filler and internal construction. The M18 was made available in four colors: yellow, green, red, violet, and used extensively in the Vietnam conflict and since. A nonsubmersible variant of the M18 was also made, with a floatation bladder to prevent it from sinking for use in marking at sea.

XM48/E1/E2/E3

A variant of the XM47 series, which is in the following section, the XM48 is a "skittering" type smoke grenade. What this means is the filler is burned internally and vented through ports in the grenade body, in effect making the grenade spin erratically. The XM48 series burns an unknown filler for a red colored smoke, probably WP or HC based, and is not known to be standardized.

Mk 1 Mod 0/1/2/3

An illumination grenade, with a magnesium filler ignited by a wick type fuze, the Mk 1 Mod 0 was first produced during the Second World War. While not conclusively so, it might be safe to assume that the Mod 1 featured an improved type fuze moving away from the simple wick lighter design. The Mod 2 featured a simplified overall design, while the Mod 3 outright replaced the single piece steel body with a two piece plastic shell.

EX 1 Mod 0 and EX 2 Mod 0

Developed as a joint project between the US Navy and the DuPont Chemical company, the EX 1 and EX 2 were part of the Target Illumination and Recovery Aid (or TIARA) program. DuPont created a number of essentially glow-in-the-dark fillers, finally settling on the non-toxic PB-155 compound. PB-155 (also known as TIARA 5) glows when it oxidizes and therefore could be used to mark things at night with minimal fuss. Developed specifically for the US Navy SEALs, the first production models were created in 1963. The EX 1 Mod 0 was a hand grenade, based on the M25A2 chemical grenade described in the following section. Testing in 1963 showed that the TIARA 5 mixture had averse effects on the functioning of the C12 fuze integral to the M25A2 design. This led to the replacement of the fuze's integral primer, the M39A1, with a model that was resistant to the filler mixture, the M5. The EX 2 Mod 0, visibly more similar to other cylindrical smoke and chemical grenades (such as the AN/M8 and M18 discussed in this section) was designed to be used as a rifle grenade using the M2 series of grenade launcher adapters.

The US Army also tested a plastic chemiluminescent grenade in 1966, utilizing the PB-155 filler and the M217 impact fuze, with negative results about the mixture's usefulness for the intended role, with the brightness and duration of functioning being "insufficient.

Chemical Grenades

M1 "Frangible" CNS and AC

The M1 grenade could be filled with a plethora of chemical compounds including both lethal and less than lethal combinations for desired effect. The M1 could be filled with either CNS, a mixture of CN in Chlorpicrin and Chloroform called a Chloracetophenone solution (which functions very much like regular CN), or AC, Hydrocyanic Acid, a powerful blood agent. Both of these compounds react with air for the desired effect and require no fuze.

M6/A1, M7/A1/A2/A3 and M54

The M6/M7 series were cylindrical riot control grenades, with a variety of fillers, including CN, CS, and DM. DM is a substance that causes a burning sensation in nose and throat and a heavy tight feeling in the chest, accompanied by a nauseating effect. All of these weapons are bursting type grenades that work by burning the filler. The M6/A1 is filled with CN-DM, the M7/A1 with CN, the M7A2 (also written ABC-M7A2) with CS, and the M7A3 (also written ABC-M7A3) with the CS in pelletized rather than gelatin capsule form. The M7A2 and M7A3 have 3 emission holes on top and one on the bottom, the M6 and M7 have 6 emission holes on top and 1 on the bottom, and the M6A1 and M7A1 have 4 emission holes on the top and one on the bottom. The M54 is a variant of the M7 series designed to be dropped for aerial launchers.

M25/A1/A2

A spherical riot control grenade, the M25/A1 (also written ABC-M25/A1) is filled with CN. The grenade is of plastic construction and is a bursting type. The M25A2 featured improved body construction, and later models were filled with CS (and possibly DM) rather than CN.

XM47/E1/E2/E3

A rubber ball riot control grenade, the XM47 series are what could be called "skittering grenades" as the gas is burned internally and vented through ports in the grenade body, in effect making the grenade spin erratically. This is designed to make it harder for the target or targets to retrieve and throw back the grenade. The XM47E3 is filled with CS, but information on the other variants is scarce. It is probably safe to assume that at least one is filled with CN, and then others might have the filler in different solid forms. The XM47E3 was the standardized as the M47.

XM58

A small cylindrical "pocket" grenade, the XM58 is a riot control weapon filled with CS.

Incendiary Grenades

M1 "Frangible" AW, GA, IM, NP, and Alcohol-Gasoline

The most common types of fillers for the M1 were not surprisingly a number of incendiary agents. The various fillers changed as the chemical technology improved, and created a number of more standardized "Molotov Cocktails." AW is phosphorus mixed with a rubber-gasoline solution that allows the compound to stick better to surfaces while burning. GA is either liquid or solidified ("jellied") gasoline. IM is a thickened incendiary mixture, and NP is a Napalm filler. Alcohol-Gasoline is self-explanatory. The AW used no fuze, but the Alcohol-Gasoline mixture used the M1 igniter, the GA used the M2 igniter, and the IM and NP both used the M3 igniter.

M14

A cylindrical grenade visually identical to the M8, the M14 (also written AN/M14) is a purpose designed incendiary grenade. Working off the intense and violent reaction of the thermite filler, end result of the detonation of the M14 is molten iron. This means the M14 is primarily employed on material to be destroyed in a roughly secure environment and not as an offensive or defensive weapon. The grenade has the ability to melt right through an engine block. Also, since the thermite reaction uses iron oxide instead of oxygen for its oxidizing agent, the grenade can work under water.

Model 308-1 Napalm

Another variant of the Model 308-1 designed by the Special Operations Branch of the Naval Weapons Center at China Lake California, the 308-1 Napalm was in direct response to SEAL requirements for a more offensive incendiary device over the M14. Issued as a kit, the user would take the included powdered Napalm ("M1 Thickener") and then fill the grenade with gasoline to produce a complete incendiary device.

Stun Grenades

M116/A1 and the "Flash-Crash"

The M116/A1 is not technically a stun grenade, but is in fact a hand grenade "simulator," designed to create a sort of realistic grenade-like effect for exercises. The M116 series is usually fitted with a pull string igniter and fuze assembly. An improvised stun grenade was however created from the M116 series by US Navy SEALs, by replacing this fuze with an M201 series igniting fuze. This new weapon was nicknamed the "Flash-Crash". There are certain dangers from using the M116-based Flash-Crash however, mainly the metal body, which has the potential to create harmful shrapnel when employing the device in hostage rescue situations.

XM84/M84

A diversionary stun grenade developed by the US Army, the M84 is part of a number of less-than-lethal and generally less harmful crowd control and disorientation weapons currently under development by the US military for use in riot control, hostage rescue, and similar situations where such a device might be called upon. The M84, like most stun grenades, creates a large bang coupled with a blinding flash (leading the common name for such grenades, "Flash-Bang"), and is readily identifiable by its two hexagonal end-caps on a perforated tube. A small charge is detonated in the center of this tube for the desired effect.

Mk 141 Mod 0

A diversionary stun grenade developed by the US Navy, the Mk 141 is a product of the same thinking that gave rise to the M84 and is designed to be used in similar situations. Looking much more like a conventional grenade, the Mk 141 is constructed of a lightweight solid foam.

Training Grenades

The following is a table of training grenades, and what grenades they are designed to mimic

Training Grenade	Associated Live Grenades
Mk II Practice	Mk II
M21	Mk II
M69	M67
M83	Practice grenade for bursting type smoke and gas grenades, based on previously issued M83s
XM102/M102	XM84/M84

Common Fuzes

The following table is of common grenade fuzes

Designation	Associated Grenades	Description
M1 Igniter	M1 Frangible Alcohol-Gasoline	An igniter containing a chemical powder which ignites on contact with the filler.
M2 Igniter	M1 Frangible GA	Similar to the M1, but with a pull wire fuze lighter, which allowed for a delay ability and more consistent detonation of the filler.
M3 Igniter	M1 Frangible IM/NP	An improved igniter using a fuze assembly with a .38 caliber blank, all set into motion by a true striker, attached by means of a Timmerman strap.
M10/A1/A2/A3	Mk II Series	A "mouse trap" type igniting fuze; ignition ignites filler
M5	Mk II (Frag-HE)	A "mouse trap" type detonating fuze, detonation sets off filler
M6/A1/A2/A3/A4	Mk II (HE-Blast), Mk III Series, M15, M34	A "mouse trap" type detonating fuze; the A1–A3 are improvements in the fuze function, the A4 features a safety clip.
M204/A1/A2	Mk II series, M26/A1, M61	A "mouse trap" type detonating fuze, 4–5 second delay, detonation sets off filler
M206/A1/A2	Mk IIIA3, M15, M34	A "mouse trap" type detonating fuze, 4–5 second delay, detonation sets off filler
M213	M67	A "mouse trap" type detonating fuze, 4–5 second delay, detonation sets off filler, safety clip
M217	M26A2, M33A1, M57, M59, M68	A "mouse trap" type electrical impact fuze, 1 second delay, detonation sets off filler
M228	M69	Training fuze with functional fuze to train on the 4–5 second delay
C12	M25/A1/A2	Integral detonating fuze, 1.4–3 second delay, detonator bursts body scattering agent
M200/A1	M6/A1, M7, M8, M14, M16, M18	A "mouse trap" type igniting fuze. Ignition ignites the filler and expels it from the grenade body.
M201/A1	M8, M83, M14, M18	A "mouse trap" type igniting fuze, 1.2–2 second delay. Ignition ignites the filler and expels it from the grenade body.
M201A1 MOD 2	M7A1/A2/A3, M84	Variant of the M201A1, designed to be non-fragmenting
M201A1-1	Misc Grenades	Training variant of the M201A1

Citations

References

Allen, Edward A. Technical Progress Report: C12 Detonator Malfunctions in EX 1 Mod 0 Illuminating Hand Grenade. China Lake, Calif.: Naval Ordnance Test Station, 1963.
Dockery, Kevin. Special Warfare Special Weapons. Chicago: Emperor's Press, 1997. ISBN 1-883-47600-3.
Gervasi, Tom. Arsenal of Democracy III: America's War Machine. New York: Grove Press, 1984. ISBN 0-394-54102-2
Hogg, Ian V. The American Arsenal. Mechanicsburg, Penn.: Stackpole Books, 2001. 1-85367-470-2.
United States Government. United States Army, Army Concept Team in Vietnam. Final Report of Chemiluminescent Hand Grenade. Army Concept Team in Vietnam, 1966.