Things that I have tried when in your situation with other guns. Using a table of some sort, put the front of the slide on the edge and push while pulling back on the rear with the other hand. If the gun is out of battery it probably won't fire, but still never pull the trigger. Is the tacke down lever back to it's horizontal position? Make sure the magazine is out of the pistol while trying any fix. The pushing using a solid table usually works.