Age of the firearm is a significant consideration in this topic. Many of the older firearms and many less expensive lines used more malleable steels.
Almost any center-fire revolver that has the firing pin attached to the hammer, tends to peen outward the opening for the firing pin on the frame window side (where the cylinder is). This is because there is no cartridge primer to provide resistence to the force of the falling hammer & pin and stop their forward motion from impacting the surfaces on the inside of the pin opening. A few of the early models which used floating firing pins & transfer bars would also peen from inside. My experience with this particular problem was with an early production Charter Arms Bulldog .44SPL that used a floating beryllium-copper firing pin. The Be-Cu pin was purportedly unbreakable, which translated into a much greater capacity to deform the pin hole.
I've seen a few turn of the century rifles that had a this problem also, including a .30-40 Krag-Jorgenson with which I deer hunted as a youngster.
The .22 rimfire pistols and rifles had a similar problem, again due to use of more malleable metal around the chamber area. The Remington 513-T rifle, older HS Victors/Citations, and the S&W model 41, have this propensity, in my experience. I use Winchester .22lr Dummy Cartridges (about $3.50 last time I bought a box)in my Victor, Hammerli 280 & S&W 41. The Dummy Cartridges can be ordered from Brownells, or a local Smith will usually have some on hand.
Peening is not the only issue here. Unless the firearm has been properly engineered for dry firing (and the more astute manufacturer will usually not miss the opportunity to hype that point!) then dummy cartridges or snap-caps should be used to prevent damage to the firing pin or the firing pin spring in those models that use one. Snap-caps can be bought at most firearms and sporting-goods stores, albiet at a considerable gouge to the wallet.
A quick and easy method to make snap-caps to protect any center-fire gun is to take a deprimed cartridge case (obviously the same as that for which the firearm is chambered) and fill in the primer pocket(even with the base of the cartridge case) with a silicone sealer (bathtub sealer, Shoe-Goo) or similar substance that dries to a resilient plug. Do not use non-drying or "tacky" substances for this. Another similar technique is to stuff a pencil eraser in the primer pocket and trim it flush with the base of the case. A little house-hold glue in the primer pocket will help hold the plug in place.