I just bought a .25cal Ortgies at a gun show last weekend. After cleaning it up and fixing a problem with a sticky safety.. I find that the gun won't cock unless I'm applying a downward pressure on the slide when I'm pulling it back. If I'm not applying any pressure you can hear the firing pin going forward as the slide does when it returns home. Any suggestions as what might be wrong with the pistol? I'm sure there's a part that probably needs to be replaced, but I don't want to go ahead and buy the wrong part to still have a non-functioning pistol.