[Ron Wood]

Heinz,
The skepticism that I expressed was in regard to the comment that "the first Navy Lugers were 7.65", not your recollection of the presentation carbine with Navy markings. I also remember that carbine post from Still's forum. It is a beautiful and desirable piece but as you have noted, the only connection to the navy is the acceptance mark which, no doubt, was applied when it was awarded and not because it was a contract item. I remain unconvinced that there was ever an issue Navy Luger in 7.65mm.

Sid, G.T. and John S.,
I think you guys are on track. The concave indentation on the Luger mag is both functional and decorative. It does provide a better purchase for extraction of a stubborn magazine, and it looks better than just a slab sided extension. The convex profile of the Borchardt magazine knobs probably was the inspiration for a more "snazzy" treatment of the Luger magazine bottom, but the convex configuration is a bit more complex to machine and finish than the concave style, plus it can be harder to grasp if you fingers are cold and wet. My guess is that the indentation of the magazine base is to improve grasping the magazine, and the difference in machining of the magazine bases between the "standard" and "Navy" is purely cosmetic.