I use them in my 38 special revolvers.
You can use either magnum or standard primers.
If you're only shooting 10-15 feet, use standard primers, put your target on a heavy cardboard box, such as those used for shipping liquor bottles. The projectiles will stay inside.
As for use indoors, I have a small fan over the ventilation grid in my basement to pull the gasses away from me and push them outside. I have a "noise barrier" outside, so as not to disturb the neighbor.
The target box is set up on a small table in the basement, just under the vent grid. This is necessary for the fan I have to pull the gasses away from me.
They're great for teaching newbies and youngsters. LOUD POP, ZERO RECOIL