First Luger; having issues

[Olddog84]

OK,
New to the forum and the Luger. Bought a '20 era commercial in 30 Luger. Using Fiocchi factory 30 ammo and 3 different mags; original and 2 Mecgar. Gun does not run with any mag. Always the same malfunction; the round try to feed nose high and jam nose up against the barrel hood. When single fed the toggle will not lock open on an empty mag. When hand cycling it looks to me like the toggle is not coming back far enough to let the mag come to full elevation. When i hand cycle and bring the toggle all the way back it will feed fine. I think the mainspring is too strong, but if anyone has any other ideas i would certainly appreciate any advice.
Mike