India (?) 7.62x51

I have 7.62x51 with the headstamp “O.K. 77 7.62 A”. I think this is made in India. Correct? What does the O.K. stand for and what does the “A” after the 7.62 mean?

The letters “OK” stand for "Ordnance Factory Khamaria, at Jubbulpore, India.
I do not know what the “A” after the caliber marking means. The same “A” appears on a “57” and “58” dated 7.92 x 57 Besa rounds that do not include a caliber designation. One guess I heard, and it was just a guess, was that was India’s designation-letter for ordinary ball ammunition. I have no idea if that is true or not. The 7.9mm Besa rounds imentioned are ball rounds.

John–Thanks for the info. I was guessing that O.K. stood for Ordnance Factory Kirkee, so I’m glad I asked.