MK3 grenade
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| MK3 offensive grenade | |
|---|---|
 Diagram of a MK3A2 grenade | |
| Type | High explosive hand grenade |
| Place of origin | United States |
| Service history | |
| Used by | United States |
| Wars | |
| Production history | |
| Designed | 1918 |
| Variants | See § Variants |
| Specifications (MK3A2) | |
| Mass | 15.6 oz (440 g) |
| Length | 5.275 in (134.0 mm) |
| Height | 5.43 in (138 mm) |
| Diameter | 2.13 in (54 mm) |
| Filling | TNT |
| Filling weight | 8 oz (230 g) |
Detonation mechanism | 4–5 second timer |
| References | [2] |
The MK3 hand grenade is a cylindrical concussion grenade.
Design
[edit source]The MK3 was designed to produce casualties during close combat while minimizing danger to friendly personnel exposed in the open owing to minimal fragmentation. It's also used for demolishing enemy fortifications and due to the greater shockwaves (overpressure) generated in comparison to fragmentation grenades, it's also effective at clearing occupied buildings and other enclosed spaces.[3]
The lethal radius of the blast is 2 metres (2.2 yd) from the impact point in the open, but there is also a secondary fragmentation hazard from bits of fuse and loose objects near the detonation—rocks, gravel, wood splinters, glass, etc.—can be projected as far as 200 metres (220 yd) from the center of the explosion.[3]
Variants
[edit source]There are three variants: the basic MK3, the MK3A1, and the MK3A2. They differ in their construction and the type of fuze used. They were designated Mk III (Roman numerals) prior to 2 April 1945.
1918 version
[edit source]The first version was created in March 1918.[4]
It was designed to be used during trench assaults to knock out bunkers and clear trenches without producing fragmentation that could injure the user or friendly forces nearby.
The MK3 has a cardboard body[5] and a crimped metal top and bottom. The top has a raised fuze well that was threaded for a fuze assembly.
It used the reliable Mk.II fuze, which used a Mills-bomb style striker but with a straight lever. It was replaced by the MK3A1.
It can be identified by its black body with yellow markings.
MK3A1
[edit source]The MK3A1 had a water-resistant laminated-paper body and top and bottom caps made from die-cast metal. The top had a threaded fuze well in the center.
It originally used the M6A1 fuze, which had a four to five second delay. It was upgraded to the M6A2, and then the M6A3 fuze sometime in the early 1940s and the M6A4D fuze in 1944.
The grenade contained 7 ounces (200 grams) of flaked TNT filler.[6]
It can be identified by its black body and a yellow band pasted across the middle marked "Grenade, Hand - Offensive MK.III A1" in black lettering. It differs from the MK3 in having a fuze well that is flush with the surface of the top cap.
The grenades weighed 0.69 lbs. (~313 grams) each.[6] The MK3, like all TNT-filled grenades and bombs, were shipped without their fuzes as a safety measure. They were packed in cardboard storage tubes in crates of 24 or 50. Fuzes were shipped separately in boxes containing 25 fuzes.
MK3A2
[edit source]The MK3A2 had a waterproof asphalt-impregnated fiberboard cylinder and its top and bottom were made from the same material.
The top had a fuze well directly threaded in its center. It originally used the M6A4D fuze, which had a four to five second delay.
This was later replaced with the updated M206 series fuze (currently using the M206A2), which was smokeless— and noiseless—burning and had a five-second delay. It contained an 8 oz. (~226.8 grams) TNT charge.
It can be identified by its cylinder, which is in two halves and is secured in the middle with a wide black band. The yellow lettering is printed directly on the surface of the grenade and reads "Grenade Hand - Offensive MK3A2 - TNT".
The grenades weighed in at 0.96 lbs. (~435.45 grams)[6] They came packed in storage tubes in crates of 30 grenades.
References
[edit source]- ↑ Hay 2009, p. 112.
- ↑ Department of the Army 1988, p. 2-35.
- 1 2 McCullough 2010, p. 464.
- ↑ Hogg, Ian; Chen, C. Peter (March 2015). "World War II Database".
- ↑ "American Grenades & Ordnance". www.inert-ord.net.
- 1 2 3 Dockery, Kevin. Weapons of the Navy SEALs, Berkley Publishing Group, New York (2004). p.237
Bibliography
[edit source]- Hay, Jeff T. (2009). Zappia, Charles (ed.). The Vietnam War. Farmington Hills, Michigan: Greenhaven Publishing LLC. ISBN 978-0-7377-4637-2 – via Google Books.
- McCullough, Jay, ed. (2010). Ultimate Guide to U.S. Army Combat Skills, Tactics, and Techniques. New York City: Skyhorse Publishing Inc. ISBN 978-1-61608-010-5 – via Google Books.
- Department of the Army (1988). TM 43-0001-29: Army Ammunition Data Sheets for Grenades. Headquarters, Department of the Army – via Google Books.