Limited dry firing shouldn't hurt most centerfire revolvers and a few months ago I would have said +3 (or whatever). Then I bought a nice, clean, barely-a-turn-line M28-2. On about the third cylinder full of ammo I put through it the hammer nose broke off, dropped into the action and, as I went "Click, click, what the heck?" found it's way against the cylinder stop where it jammed. Getting the cylinder open left a nice scratch between two of the notches. A new hammer nose and she's back in business, but I suspect whoever had it before me spent more time dry firing than live firing.

Now I would invest in a set of A-Zoom snap caps, then dry fire away. The caps will more closely simulate the weight of a loaded gun, and the action will only improve with use. That firing pin was designed to hit something when the hammer falls.

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I need ammo, not a ride.