Friend of my uncle had sporterized Mauser 98 whitch was made for his father before WW2 for target shooting/small game hunting. He had one original cartidge left (rifle was later rebarreled for 7,62x53R). It looked lot like 7x54 Finnish, but bullet diameter was closer to .30 cal (it was hard to measure it because the bullet was so short). Bullet was small nickel plated full metal jacket. If I remember correctly, case was 6,5x55 Swedish made by DWM.
Uncles friends father had 7,65 Luger/Parabellum 08 pistol. Was this some kind of wildcat made to shoot 7,65 pistol bullets, or was it some kind of experimental caliber, or did I simply made mistakes when measuring bullet... Sadly uncles friend died some time ago, so I can't chek the measures.
Probably it has nothing to do with 7,63x54 Greek M-S.