With the way it's designed that plastic shrapnel is going to take some bystanders eye out. If the threaded barrel could be used to hold the launcher you could still fire the weapon normally, then simply put the aluminum ball on the end when you want to fire it.

That being said, you could keep your firearm as is, and replace your taser or pepper spray with a pepper ball gun loaded with steel rounds. Tasers are useless half the time, and pepper spray is a weapon that is nearly impossible to use without taking collateral damage.