.224 Centerfire for the Luger???

[Ponyman]

Check out the .22 Reed Express. It's a necked-down 7.62x25, and might be compatible with P08 magazine dimensions - case and rim diameters are.002 inch smaller than the Luger. The case is a tad longer than a 7.65 Luger, but a smaller (round nosed) bullet might result in a usable over-all length. They're claiming 783 ft-lbs muzzle energy, so you would have to load it down - or find a heavier recoil spring - to use it in a properly chambered Luger. The groove above the rim is squared off, and might pose a problem for the Luger extractor. The barrel, in any case, will be strictly custom. Unless, of course, a large enough group of buyers were to approach Reed's Ammunition & Research with a quantity request..... Brass & dies are currently available.

http://www.reedsammo.com/

There's more info at Ammoguide.com - but you have to be a subscriber to see it.