2 Pounder Anti tank / Plate test.

[Bockscar]

I acquired four of these projectiles recently and although they are fired examples they shall go well in the four empty cases that I have had for some time.
All were suffering from the passage of time, but one has been cleaned up to show the original turning marks and has revealed the following stampings:

APP 2 Pr Mk1
H.L I 8. 43
FK 107 .9

At first I thought the APP may indicate Armour piercing practice, but I now think that Armour piercing Proof may be more likely. Once again on learning that these projectiles came from a research establishment, I think that this more likely to be the case.
The other three so far uncleaned, bear the same stamp "APP" so its not a typo.
The single example image shows signs of white paint to the body.

Bockscar

 

[gravelbelly]

I have one of these 2Pr A.P.P. projectiles which has almost, but not quite, passed right through the armour plate. A large scab of the plate now sits just in front of the driving band like a ballerina's tutu (skirt).



gravelbelly

 

[Bockscar]

Dave,

I remember seeing this on my visit to you....it certainly did its job right didn't it!

Bockscar.

 

[Bellifortis]

I have a general question to the designation 2-pounder. How does this relate to caliber ? If I'm not mistaken the british pound is 452 grams. Modern ( the last 200 years ) practise generally takes the diameter of an iron ball of so many pounds to be the caliber. Some older systems use stoneball weight and for the smaller calibers lead ball weight. So, this is sometimes very confusing. What's the current british practice ?
With kind regards and wishing you all a good new Year 2015,
Bellifortis.

 

[Vasco Da Gama]

Ready to be corrected but the projectile weight does not directly relate to calibre as in smooth bore cannons. For example the following guns were of 76.2mm calibre: 15pdr field gun, 12pdr naval and Coast defence, 13pdr field gun and anti-aircraft and 17pdr tank and anti-tank. These examples stretch from early 1900s to WW2, so you can see the description is merely the weight of the fired projectile and does not immediately indicate the calibre. However some common examples are: 37mm 1pdr, 40mm 2pdr, 47mm 3pdr, 57mm 6pdr, 84mm 20pdr, and 88mm 25pdr.

 

[tigbrand]

Hi, APP denotes AP practice,yours are steel,they also come in cast iron and marked CI. And there are various marks with different tracer arrangements. Cheers Tig.

 

[Bellifortis]

Thank you for your answer. But, especially with the nice examples you give for the 76,3mm calibre, what made them be designated as 15, 12, 13 or 17pdr ? There must be a system these designations are based on.
Regards,
Bellifortis.

Ready to be corrected but the projectile weight does not directly relate to calibre as in smooth bore cannons. For example the following guns were of 76.2mm calibre: 15pdr field gun, 12pdr naval and Coast defence, 13pdr field gun and anti-aircraft and 17pdr tank and anti-tank. These examples stretch from early 1900s to WW2, so you can see the description is merely the weight of the fired projectile and does not immediately indicate the calibre. However some common examples are: 37mm 1pdr, 40mm 2pdr, 47mm 3pdr, 57mm 6pdr, 84mm 20pdr, and 88mm 25pdr.

 

[Vasco Da Gama]

I would offer that the designation is based upon the weight of the primary projectile the gun was designed around. The 13&15pdr would have been designed around a shrapnel shell. The weight of the projectile would have come out of the design work aimed at delivering the required performance, velocity, range, rate of fire and lethality of the projectile. The 12pdr as a naval weapon would have had a semi-armour penetrating shell and velocity would have been important to deliver kinetic energy 1/2 MV-squared. Better to fire a lighter projectile faster, to give increased amour penetration. The 17pdr was designed for pure armour penetration and the weight would be combined with the velocity in order to defeat the desired target, probably the front plate of a Panther or Tiger tank at a reasonable range.