Back in the 1950’s I bought a very old .22 revolver that was an unusual name brand to me. It seemed okay until I looked closely at the back of the cylinder and saw the deep (peen) marks from the firing pin striking each cylinder hole with no shell in place. The cartridges were a problem to load and extract until I removed the bur in the chamber. The dips were narrow but deep enough I was surprised it fired okay. The fired shells were not only indented on the outside but bent downward on the lower-side to form a wrinkle when looking sideways.

I read that some semi auto .22 pistols and rifles have safety pins that stop the firing pin before it hit’s the barrel when empty. I dislike having to leave a 22 semi auto cocked in long storage so consider it nice when okay to snap them off. I have read that sometimes a safety pin gets broken or someone cleaning gun forgets to put one back in.

Sometimes I have put a small piece of writing tablet paper on the front of the chamber to see if the firing pin smashes through the paper with one or two hammed drops.

(Lawyer warning - never do this)
Finally I decided to use a fired shell rotated slightly past the previous indentation. That worked very well for releasing hammer spring tension for storing a hammerless semi auto 22. (A purist would never leave an empty shell in a chamber but I am not a purist) So I also began using fired shells to dry fire my 22 revolver. Each time I clicked on all six chambers I opened it up and rotated each shell slightly more than the width of previous indentation. I did not have the type cylinder that was cut inward to surround the head of the shell, but I doubt it would make a difference.

In this day and age of lawsuits no manufacture would ever recommend dry firing on empty rim-fires so I guess I also will not recommend it either. Also never drink alcohol or talk on telephone when dry-firing unless your kids are grown, you are over 50 years old, and can ignore women really well.