I wanted to dry-fire practice with my .22 autoloader, so a long time ago I got a mess of those plastic .22 dummy rounds to avoid dinging up the chamber rim. (Some guns have a firing pin limiter so this doesn't happen, but mine doesn't.)
I would load up a mag full of them and yank the slide for each dry-fire session.
They're OK, but suffer from a couple of problems. When the firing pin hits, they dent, and when you pull the slide to recock the thing, sometimes they eject, sometime they don't, so the following plastic round jams in there. Even turning them around just postpones the inevitable. Sooner or later the whole rim is smashed down by the successive firing pin impacts and they become useless.
So what I did today was take a fired .22 case and trimmed off a part of the rim (wire cutters, file) so the extractor won't grab it, then put the trimmed case into the chamber so the cutout is under the extractor.
That way I can use only one, without the magazine, and just rack the slide for each "shot." Yes, the rims get flattened under the firing pin, but at least the brass can take more impacts than the plastic.
Ejection is accomplished with a cleaning rod.
Not an earth-shaking idea, but may come in handy for dry-firing with other rimfire guns.
Terry, 230RN
