40 MM Plate Test Projectile.

[Chris 42 RQ]

Here is a "Plate Test" projectile, this and other similar rounds were used to test the resistance of various types of Armour plate during the developement phase of Armour types like "Chobham" Armour.
With a calibre of 40 MM they were usually fired from a 40/70 Bofors Barrel with a varied charge for different velocities.
This one is constructed of a "Tungsten" core housed in a "Magnesium" body with screwed on "Nylon" driving bands-as you can see it is slightly corroded as "Magnesium" is very sensitive to Moisture.
The projectile will have been separately loaded with a cartridge behind it similar to B.L. Guns.

 

[spotter]

whats the reason for the magnesium

 

[Chris 42 RQ]

Magnesium is generally used as the round is usually fired into a "Stripper Plate" to remove the "carrier" (body) as that is not what is required to hit the target.
The body which is made of a rigid material so that it delivers the sabot (Tungsten core) with accuracy and in some cases a "spin" is required to be given in which case the tight fit of a fairly "non-elastic" (Magnesium or Aluminium alloy) will ensure that the core is spun correctly.

Nylon has been used but you generally fire Nylon sabot's from smooth bore guns as it is a fairly "elastic" material and therefore tends to spin around on any item held within it.

Also when machining this material it is possible to machine it to fine tolerances
Hope this answers your question.

 

[spotter]

Thanks for explaining chris

 

[Chris 42 RQ]

One thing I also forgot to add was the fact that "Magnesium" is a very lightweight material and therefore does not reduce the velocity of the item it is delivering to the target-that is one of many reasons that the vast majority of "Sabot" rounds consist of heavy cores in Aluminium "Sabots" .