Hollywood has seen to it that the American perception of all hand grenades is a pineapple shaped device with a pin that the GI pulled with his teeth. Like many movie-fueled ideas, this one has some flaws, especially when it comes to the grenades GIs tossed during the Vietnam War.
THE CLASSIC MK-II PINEAPPLE
When U.S. troops first arrived en masse in Vietnam in 1965, they did, in fact, use the classic MK-II "pineapple" grenade. This 20-ounce grenade had served with the GI from the 1920s, up the beach at Normandy, across the black sand of Iwo Jima, along the frozen Chosin Reservoir before coming to Vietnam. But Vietnam was to be its last battle.
Due to the length of time that the MK-II was in production, there are numerous variations. Notably, in 1942 the color of the high explosive-filled grenade body changed from yellow to olive drab with a yellow band. By 1944, these grenades no longer had a threaded filler plug in the bottom, but rather had a solid base. Collectors often refer to this style as the MK-IIA1, but this author has discovered no documentation to support this designation. About the same time the base plug was eliminated, the M6 and M10A3 fuses began being used.
The pineapple shape was a result of indentions intended to cause the grenade to fracture into uniform pieces of shrapnel upon detonation. This detonation was caused by pulling the safety pin, and releasing the arming handle, which set into motion a five second delay fuse. Too often the delay time varied, sometimes with tragic results. Accordingly, the improved M204 fuse was installed in the MK-II grenade during its post World War II use. The M204 had the added benefit of being silent, and not emitting sparks or smoke.
THE "LEMON" GRENADES
The M26 and M26A1 grenade supplemented the classic pineapple in the hands of GIs during the Korean War era. The purpose of this design was to improve the grenades fragmentation characteristics. The heavy cast steel of the MK-II sometimes was projected back to U.S. soldiers due to its inconsistent fragmentation. The smooth steel shell of the new 16-ounce grenade was filled with flake or granular TNT, and detonated by a M204A1 or M204A2 fuse. From the standpoint of the grunt, this fuse operated in the same way as had the fuse of its ancestor — but with a notable improvement in reliability. The M26 was soon replaced by the M61 as the Army's "new" grenade, but vast stocks of the MK-II remained in inventory.
Once supplies of the MK-II were exhausted, the M61 became the primary grenade used by U.S. forces in Vietnam. Due to its shape, the M61, like the M26, is sometimes referred to as a "lemon" grenade. Since the M61 is basically a "product improved" M26, it too had a steel body with internal fragmentation coil. The M61 has an extra safety (called the "jungle clip").
GIs have long carried grenades loose on their uniforms, often by the arming lever —despite admonitions not to. It was found that jungle growth often snagged on the grenade, causing it to arm, with predictable results. Accordingly, an additional safety clip was added to the tried-and-true pin and lever style fuse. Commonly called a "jungle clip," this secondary safety device held the arming lever to the grenade body, even if the pin was pulled. This added an additional step—releasing this clip—to the use of the grenade.
THE "BASEBALL" GRENADES
The M61 did not serve as long as had its predecessor. Late in the Vietnam war, the M67 began to replace it. This baseball-shaped grenade is even lighter than its predecessor. Smooth on the outside, the inner portion of its brazed metal shell is embossed in a dimple pattern to aid fragmentation. While practice grenades lack this feature, the embossing is sufficiently heavy that it is sometimes visible, especially at the bottom, of genuine fragmentation grenades.
The "lemon" and "baseball" grenades were finished in olive drab. Most had yellow markings and top band to denote a high-explosive charge. The M26 and M61 are typically found with bodes baring the following markings: LOP (Louisiana Ordnance Plant (Shreveport)), LS (Lone Star Ordnance Plant (Texarkana)), MA (Milan (Tennessee) Army Ammunition Plant), OA (Ordnance Associates Inc., South (Pasadena, CA). The grenades were individually packaged in cardboard cylinders, and thirty such cylinders were packaged 30 per wooden case.
Once again, the band markings and lettering were done in the U.S. standard for high-explosive — yellow. The charge in this case is 5.4 ounces of Composition B explosive, fused with a 4.5 to 5.5 second delay by means of a M213 fuse.
The M67, like some of the M26 grenades, is often found with bodies marked "JA" denoting the Joliet Army Ammunition plant. The M67 remains in use by U.S. forces worldwide today. With Fiscal Year 2004 production estimated at 400K per year for 2005 through 2008, it will be a long time before this grenade is considered scarce.
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