Pineapple grenade

[Sentryduty]

Does anyone have any evidence that the raised sections are intended to fragment and if so could we see it, please?

I do not have any evidence to share but I do have a good understanding of explosions and am experienced in the use of grenades.

Re: Theory of waffle designs in grenades for fragmentation.

It makes sense in a manner, if an iron sphere is cast perfectly with no imperfections and variations in composition it should explode into equal little pieces. By casting in designed weak points in the structure (in a waffle pattern) it would be reasonable that the grenade would split at the thin sections and distribute little injury inducing cubes of iron in a uniform and radial pattern.

However once we leave the simple blackboard, the whole plan falls apart.

Grenades are not perfect spheres.

Casting is not uniform.

Due to the delay fuse, the explosion is not initiated perfectly centre inside the grenade body, it is usually towards a certain side which aids:
The engineered weakness in the waffle casing is not the weakest part of the grenade body, in most cases stress risers will initiate cracking near the edges of the fuze hole or other orifice.

Explosions are just expanding gasses and will try to escape containment, always seeking the path of least resistance, once a crack is formed all of the gasses will try to escape through that one rupture point.

Once that crack has opened far enough, and the explosion has built sufficient pressure the grenade body will break apart along that fault line and disassemble into randomly shaped pieces.

Here is a modern M67 note the "peels" from top to bottom.


German Egg grenade dig ups:


Two piece besozzib design, failed where it screws together and only generated 4 lethal fragments.


I can't comment on the original intent of Mr. Mills design, but I can say that Grenades (and other sundry offensive explosions) generally kill from blast, while perforation of the body by the casing is obvious if one is unlucky enough to catch one, however other small fragments projected outwards from the explosion can prove fatal after the initial injury.

I have personally been 3 metres away from an exploding M67 fragmentation grenade on open, level ground, and I came away uninjured by simply lying prone. If the same situation were to take place inside an enclosed area like a bunker, or vehicle, I would not have come out unscathed.

Further reading on hand grenade mechanism of injury from this medical incident review, jump to the "discussion" section for summary:
Hand Grenade Blast Injuries: An Experience in Hospital Universiti Sains Malaysia