Original Item: Only One Available. This is a U.S. WWI Mk I fragmentation hand grenade, the first standardized American fragmentation grenade developed during the First World War and the direct predecessor of the much better-known Mk II "pineapple" grenade. Introduced in 1917, the Mk I incorporated a deeply segmented cast-iron body together with an unusually complicated fuze and safety-lever arrangement.

This example retains the distinctive Mk I lever assembly and safety pin, immediately setting it apart from the later Mk II pattern. The cast-iron body exhibits the characteristic heavy external segmentation and retains an appealing dark aged finish. The body shows scattered surface oxidation, while the exposed steel components have developed a lighter gray patina. Despite the expected age, the segmentation remains strongly defined and the grenade presents very well. The fuze threads are no longer functional, and the fuze is presently secured in place with adhesive. It can still be moved with firm pressure, but it should be considered fixed in position.

Of particular interest are the markings cast into two adjoining body segments. The upper marking consists of a prominent 4, while directly below is a clearly defined diamond-shaped cartouche containing an F. Similar diamond-F marks are known on surviving U.S. Mk I grenade bodies, often accompanied by differing numerals. The precise manufacturer represented by the diamond-F marking has not been conclusively established. The accompanying 4 appears to be a production, lot, or casting identifier.

The Mk I was developed after the United States entered WWI and found itself without a satisfactory domestically designed fragmentation hand grenade. American troops initially relied heavily upon foreign patterns, particularly British and French grenades. The new Mk I was intended to provide an American solution, but its elaborate safety and initiation system proved too complicated under battlefield conditions. Troops could fail to properly arm the grenade before throwing it, and the design was consequently withdrawn after only a relatively short service life. It was replaced in 1918 by the much simpler Mk II fragmentation grenade, a design that would remain closely associated with American forces through WWII.

Because the Mk I had such a brief service history, surviving bodies retaining their distinctive early lever arrangement are considerably less commonly encountered than the later Mk II. This is a particularly recognizable example of an important transitional stage in the development of the American fragmentation grenade.

This inert ordnance item has been fully deactivated in accordance with ATF guidelines. It cannot be converted into a functional explosive device and is strictly restricted from international export.

Totally inert, cannot be converted to an explosive device, not available for export. This item is completely legal within the USA. International Military Antiques, Inc observes all Federal, State and Local laws. Everything for sale on ima-usa.com is completely legal to own, trade, transport and sell within the United States of America.

All deactivated ordnance sold by IMA, Inc is engineered to be inoperable according to guidelines provided by the US Bureau of Alcohol, Tobacco, Firearms and Explosives (BATF).