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Vivien-Bessières Rifle grenade and launchers. Part IV

[The original of this series of posts has apparently been lost in the mists of time and some hole of the blog back-office, orphaned during the last update - so I'm reproducing it here. It's going to be new to most of you, anyway...-the Armorer]

The Grenades.

There were at least three types of grenade made for the V-B system. First, was the standard HE grenade, which US industry produced over 20 million of for the war. Next was a message grenade that was used by the French, but rejected by the US. Lastly (that I’m aware of) was a pyrotechnic grenade, used as a carrier for flares, star clusters, and smoke.

Like the launchers, the US V-B grenades were essentially the same as their French forbears. The main difference between the two versions of the HE grenade is that the US grenade was made out of malleable iron instead of cast (brittle) iron. Both grenades were serrated internally to assist fragmentation – and because external serration would increase gas loss (and matching range loss) during launching. As John Heinrichs noted in comments to the earlier post on the subject – many grenades were serrated externally to improve the soldiers grip, and that the serration was for that purpose – it being known that external serration was ineffective in assisting controlled fragmentation. The historical record is mixed. There are US records dating to WWII where it came as a surprise that external serration was ineffective – perhaps simply because if anyone had tested prior to that, it was unknown to the then-serving officers on the Board.

I suspect it’s all correct. Some people and manufacturers knew, some didn’t, and most didn’t care in any big way.

Anyway, back to the story… The grenades are about 2.5 inches long and 2 inches in diameter (you metric-types can do your own conversion…) and weighed 17 ounces or so, just over a pound. They had a range of about 200 yards when fired at 47 degrees, and a ‘danger zone’ of 75 yards from the point of burst. Since the range exceeded the bursting radius, the grenade was considered both ‘offensive’ and ‘defensive’. The distinction being that an offensive grenade has a smaller bursting radius than its average throwing distance – i.e., it can be used by a soldier in the open, whereas a defensive (generally more powerful) assumes the user is under cover.

The pyrotechnic grenade (cylinder in the middle) was simply a carrier for combustable material, whether phosphorus or some other incendiary compound. They weren’t very effective and didn’t see much use.

Last, but not least, is the ‘message grenade’. Intended for use by cut-off units, it contained a tube into which a message could be inserted, and the grenade then fired. Upon landing, a small smoke charge would go off to make the grenade more visible. Several problems arose. The smoke charge was too small, consequently, it was hard to see. The fuze failed to function in soft ground. Until the somewhat mobile battles of late 1918, pretty much all the ground people were fighting over was soft ground from years of pounding. Lastly, if you were cut off, you couldn’t tell anyone you were going to be sending messages, so they wouldn’t be looking for them when they landed. If they were trying to get to you – same problem, exacerbated by the fact that cut-off and surrounded units are many times closer together as individuals on the battlefield… and getting hit with one of these things, well, sucked.

Here endeth the tale.

If you stumbled into the middle of this - the beginning is here.



I REALLY WANT examples of both types for the M1903 rifle, either the straight slot of the corkscrew type!
I believe some Confederate arsenals cast shells in which the cavity was polygonal, to ensure fragments of uniform useful size.  Nothing new under the Sun.