Luger Newbi Question???

[BigBarn]

Hi too all;

I am a new member to this forum, and also new to the world of Lugers. I have purchased my first one, and it is in remarkable shape, and shoots like a dream, except for one little problem: Every time I shoot, and it ejects the spent shell, it goes back into battery with the next round, but for some reason, the firing pin is not cocked, and it will not fire when I pull the trigger.
I can pull the slide back far enough to **** the trigger, and then it will fire just fine, but the same thing happens when I fire the next round, it will not **** the trigger.

Any suggestions? I am using new Winchester FMJ ammo, 124grn. And everything else seems to function perfectly. Also, when it is unloaded, with the magazine out, it will **** the trigger everytime I pull the slide back as far as necessary. Seems crazy to me, but then I do not know much about these fine weapons. hopefully one of you experts can help. Thanks in advance for any and all suggestions.

BigBarn