I bought these for a fancy dress party... and a bit of nostalgia. I must be getting old, because I'm starting to understand the sentiment behind phrases like "They don't make 'em like they used to".
When I had caps as a child (about 25 - 30 years ago), they made a massive bang when they went off and cap guns and bombs were outside toys becuase of this noise.
Not any longer: these are pointless. Loading these into my gun barely changes the sound it makes when you pull the trigger, and it's not a loud mechanism. If you're not concentrating, you only know the cap has actually gone off by the smoke, the smell (which, thankfully, hasn't changed at all!) and the occasioanlly visible flash. The gun, by the way, is an open cowboy-style revolver, not one with a hidden mechanism that might muffle the sound.