The guy who posted that video says to leave the slide retention lever at the 12 o'clock position when trying the slam the slide home (or tap it with a mallet). Don't do that. Leave the lever at the 9 o'clock position, where it is normally.
When the lever is at the 9 o'clock position, the slide is kept from moving forward by both the slide retention and the sear. If you have the lever at the 12 o'clock position, the only thing keeping the slide on the frame is the engagement of the sear and the nose on the striker -- which is why when you pull the trigger, taking the sear out of contact with the striker nose, the slide comes off easily.
So by forcing the slide forward with the lever at the 12 o'clock position, you could be putting a lot of stress on the sear/striker.
Someone correct me if I'm wrong.
