I added a hole in the center after being told to shave my plunger rod. For a stock plunger this isn't a problem because eventually you'd be getting an exPT from Worker. But if you already have a nice and new Worker exPT I'm fairly certain you don't want any unnecessary damage before even using it. Also eventually making another remix that will use DartKarfts retalicon spring spacer so you won't have to drill holes in your shell or powerstock. Final note, this has been printed and tested so have fun running 200fps sleepers.