Kynoch 50 cal id please

[SG500]

Way outside my collecting area, a friend gave me this.
Could anyone help with the interpretation of the head stamp please?
Kynoch
1970
But what does the rest mean?
Thanks in advance.
Dave.

 

[justin]

Dave, MG Observing XL13E1 is the experimental version of the tank ranging cartridge, the L13A1. The bullets for the experimental version varied in weight until being settled on at 965 grains.

 

[SG500]

Thanks Justin, useful information.

Dave.