We shoot the Speer Plastic caps in .38spl and 'Almost' have it figured out when to stop before the smoke alarms go off. Just hard to stop when the competition heats up and we get to laughing so hard.
When warmer I set it up in the backyard. Back in September my 5 year old Grandson tired of the BB and Pellet guns quickly. But loved shooting these out of his Grandma's 5 shot Taurus. He said being louder meant it had more power.

If your wondering I can't pull the batteries, ours are hard wired, battery back up if power is out.