I don't think there is such a thing. You would have to get a reloader to make U a dummy bullet or two. I hear reloaders say they do this all the time w/ pistol rounds. Put some silicone where the primer is and let it dry.
I have only dry fired it 1 or 2 times. I don't wanna mess it up. But yea, it would be nice to practice. W/ my laser, I could see how much I am moving the gun.
Take a used shell, put a bullet in, and replace the primer with a piece of clued in rubber.
That way, it's easy to make like 10 of em, it would cycle correctly, when fed from the magazine, you can pull the trigger without any chance of damaging the firing pin (rubber absorbs the punch, while a already shot primer would not), and you can even paint it, so you don't take it as live ammo.
The Primer on a used shell is easy to remove. Just take a fine punch (or a long fine nail), and stick it through the opening where the bullet was. Then simply punch out the primer, and you have a rimmed hole, where you can glue your rubber in.
I made many of these in the past, and they work great.
I was answering for those of us that can't reload or don't know how.
I have no means to load a bullet into an empty shell casing so that my "poor-man's" version of a snap cap for those that are in the same situation as I.