it would take SO many dryfires to damage a gas gun, part of sniper school is dryfire on a empty chamber thousands of times and i have yet to see it do anything to a single gun (gas or bolt).
Dummy rounds aren't essential to dry firing, maybe another type of training, I don't know. But for the purpose of dry firing, it's not required. And to answer the question, pretty much any modern firearm can be dry fired, that includes the POF.
Sorry...I didn't make my post very clear. For dry firing alone...I agree (although some rifles/pistols do need snap caps or similar because of the possibility of breaking firing pins/destroying springs if dry firing on an empty chamber). I was referring to using them for general training, i.e. - loading/unloading, clearing jams/malfunctions, general operation of the rifle, etc.
Anything that goes by the name "T.I.T.S." is beggin to be played with!
I dry fire mine a lot. The single-stage pull is crisp, but it is fairly heavy, so I like to put my scope on max and practice keeping the hairs as still as possible through the pull.