British 7.62mm NATO API

I am slowly selling off my cartridge collection and in order to dispose of it I am reluctantly having to inert it all. In order to comply with the law here in the UK I am having to remove any armour piercing cores or incendiary compound from the cartridges before selling them. Amongst my early British 7.62mm NATO cartridges I had this cartridge which I have catalogued as ‘armour piercing’ due to its only marking being the green primer annulus. In order to render this bullet legal I had to cut through the jacket below the casemouth exposing the rear of the armour piercing core. The core can then be pulled from the jacket. I expected to find the area in the nose of the jacket to be filled with lead however I was very surprised to find it was a fine grey powder - incendiary compound!
Tony Edwards produced an excellent and very comprehensive document entitled ‘Early British 7.62mm’ in which he describes all of the early rounds he could find information on in detail. He included photos of any that he also had in his collection.
Below is his paragraph on the ‘armour piercing’ cartridges which is very thin on information compared to the rest of his document suggesting he didn’t have examples of any. The Figure 7f Tony refers to is a computer generated image of the headstamp.

**Armour Piercing **
Both Armour Piercing and Armour Piercing Incendiary rounds had been developed for the British 7mm series, but there was no service requirement for such loadings. However, there was some development of a 7.62mm AP round but little is known about it. Examples exist with the “RG 53” headstamp and a green primer annulus. (Fig.7f)