2009/05/10

Ricochet vest - too good to be true?

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A new type of Russian bulletproof vest appeared in February. It can supposedly stop AK and SVD bullets on a decent area at only two kilogram weight. And it's thin.

That sounds too good to be true.

Superlight armour jacket announced

Russian Innovation: Ricochet Lightweight Jacket

The vest, called ‘Ricochet’, solves the problem shared by all body armour designs that use ceramic or metal plates for protection. Regular plating can be pierced relatively easy if a bullet hits it at an angle close to 90 degrees. The new jacket uses a large number of small balls made from a special alloy. An incoming bullet is almost guaranteed to ricochet from them, helping the armour absorb its energy or deflect it completely, reports Rossiyskaya Gazeta newspaper.
note: "... almost guaranteed ..."

The principle is well-known. Some German tanks and especially assault guns were vulnerable to the ubiquitous Russian anti-tank rifles in WW2. The side armour was too thin. The problem was reduced by adding a kind of wire mesh. The bullets were almost always deflected by the mesh and the subsequent impact on the side armour was usually not penetrating. The principle is highly unreliable, though - some bullets passed through gaps undeflected or were deflected to a better impact angle. More reliable plates were preferred instead.

That example had a wide spacing, while this vest is very thin. I suspect that a few cm of necessary depth are being bought by accepting a deep blunt trauma - that's just like the "almost" a hint that this vest - if it works at all - is probably an 80% solution that won't pass the ballistic vest standard tests without penetration or unaccepted trauma.

The jacket can stop a close range shot from a Kalashnikov assault rifle or a Dragunov sniper rifle, says chief designer, Colonel Andrey Kochubei from a police academy in the city of Volgograd in Russia’s south.

Thanks to the novel design the ‘Ricochet’ vest is very light. It weights just two kilograms as opposed to the standard issue for the Russian police, which weights ten kilograms.

I doubt that 10 kg vests are really standard issue for Russian policemen, but the two kg figure is simply revolutionary. It's so low that I'm enticed to consider whether a weight saving of about 6-7 kg is worth a 10-20% sacrifice in bullet stopping chance. That would - if real - be very interesting for mountain warfare at least.

Two kilogram is on the other hand so lightweight that the figure itself casts doubts about the credibility of the claims. Even titanium alloy balls would have some weight, four kilogram would be more believable as the backing kevlar vest itself should already weigh about two kilogram. So I suspect that front and back part weigh two kilogram each.

Nevertheless, it reminds us that innovations can come from everywhere. The Russians have still many engineers and scientists.

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