While I take no responsibility if you bugger your gun up, 1 dry fire? No damage. 5 Dry fires? No damage. 50 Dry fires over the firearms life, no damage. 100 consecutively? BAD IDEA.
The big problem from dry firing comes from free floating firing pins, the SKS in particular. Enough dry firing and you WILL stick that pin in the forward position. Spring loaded firing pins, unless you've got a real Weighty hammer, or a Lightweight/soft firing pin, you should be ok, just don't go nuts with it. I've never seen a gun break from dry firing.
Of course, I've also never seen a round Hangfire (I've seen duds, bad primers, but never a delayed fire). Doesn't mean I'm gonna look in the muzzle to see what's wrong.