Here we have the BPD hand grenade, one of the early defensive hand grenades used by the Italian Army during the Great War.
And no sooner do you see one, than another, admittedly battered, one comes along. The initials BPD stand for Bombrini Parodi-Delfino, a gunpowder and explosives company founded in 1912 and located in Colleferro, south of Rome.
Introduced early in 1916, these grenades were far from popular, from what I can gather. The cylindrical body was made of cast iron with an overlapping seam (see top left example above), on which the head was screwed, the whole thing weighing in at around two and a half pounds. There was no pre-determined fragmentation pattern, either inside or out, and because the grenade, despite its weight, carried just two and a half ounces of explosives, it was prone, like the S.I.P.E. we looked at last post, to simply splitting in two on exploding.
The explosive used was Ballistite. And who patented Ballistite? That old peacemonger Alfred Nobel, no less, in 1887. In fact, the French got very cross with him when he licenced the rights to Ballistite to the Italian Government and opened a factory in Turin, despite having turned him down when he made the offer to them first, and more or less banned him from working in France for the remaining years of his life, which he spent in San Remo in Italy.
Diagram showing the working parts. This grenade used a percussion fuse, the first such grenade used by the Italian Army, I believe.
The basic operation involved unscrewing the brass cap,…
…and then striking the ‘incudine porta capsula con innesco’ (which translates as ‘capsule holder anvil with trigger’ – check out the diagram again) hard against a solid surface, breaking the ‘cilindretto di polvere nera’ (black powder cylinder) which in turn ignited the fuse. And if this failed to work, the grenade’s designers had helpfully added a small hole in the rim of the head (visible above) through which you could manually relight the fuse. Rather you than me! And indeed, one of the drawbacks with the BPD was the fuse itself – if you once again look carefully at the diagram, you will see that the ‘miccia’ (fuse) is shown in two places within the grenade’s head, and I am pretty sure that the fuse was placed within the head in a spiral position (something like my mock-up inset diagram below)…
…before reappearing here, slightly off centre in order not to impede the breaking of the black powder cylinder, on the underside of the head. Which probably explains why the fuse took some fourteen seconds to burn, giving ample time for an enemy soldier to throw the damned grenade back at you if you threw it too soon.
In the centre of the body of the grenade there was some ‘fulmicotone’ (‘guncotton’ – see diagram again),…
…which in this case was nothing more than a rolled tube of flash paper. Nitrocellulose is a highly flammable polymer that can be made by treating cellulose with nitric acid or a similar nitrating agent,…
…and so treating the natural cellulose in cotton with acid creates guncotton, and treating the natural cellulose in paper with acid creates flashpaper. And flashpaper does exactly what it says on the tin, which is why magicians still use it for tricks involving fire, and early grenade designers used it as a detonator.
So there you have it. The heavy, unreliable, liable-to-be-chucked-back-at-you, Italian BPD hand grenade.
The first one looks like a water bottle.
Nitrocellulose was used as the first flexible photographic film base.
Which caused the loss of many of the early films when storage rooms were destroyed by fire.
Yes indeed. Good point, for which I thank you.