I‘ve been getting some indoor trigger time with this Taurus M990 9-shot .22lr
I use Colibri primer-only rounds in a well ventilated basement room with exhaust fan and have a hepa filter running… but I still limit myself to 9 shots (I hear the primer has some lead residue and isn’t good to breathe much of the smoke)
the 20gr projectiles are pushed to about 400fps via the primer charge
the box is filled with a bag of shredded rubber… the kind used on playgrounds, etc
I also break out the other .22lr handguns and give them a go once in a while… of course, the slide does not cycle on auto loaders with primer-only loads
I have some of those Speer plastic rounds that shoot a plastic bullet with just a primer. For several years now I have been saying I want to shoot in my basement during the winter and have yet to do it. Some day...