NEVER dry fire it -- particularly Rossi's or S&W's, with the firing pin on the hammer. Or any of the older Colt SA's with the firing pin on the hammer. It's just a question of time until you break one.
Get snap caps. ( less than $10 for a set of 6 on amazon or ebay) If you get the spring-loaded ones, they'll last a long time. Or, if you're reloader, size up some 38 spl cases, fill the primer pocket with a drop of silicone caulk, and make sure it's flush with the case. (I'm a cheap son-of-a-gun)
Two quick notes: if you don't have reloading gear, cleaned fired cases will work, just fit a tad snugger. but you'll need to pry out the primers.
finally, NEVER dry fire a .22 caliber. On a center-fire cartridge, "hypothetically" a dry-fired firing pin hits empty space. But on a .22, the firing MUST contact the cylinder, which acts like an anvil when you're firing a round. You may not break the pin right away, but even if it doesn't break, you'll slowly damage it.
I know, I know, I know. there are zillions of shooters who dry fire all they want and never have a problem. ( And on a Glock, you must dry fire it once before taking it apaprt.) But I wouldn't take a chance. Sorry to lecture so long, it's just one of my hot buttons, having learned the hard way by shelling out big bucks replacing a firing pin on a used gun.
