Dry firing won't hurt anything, and is good practice.
In a pistol with a trigger job, the hammer/sear engagement can (and should) be protected: always have the trigger pulled back whenever the slide goes forward, so that the hammer and sear do not batter. Some folks object to this on the grounds of safety, but that's how the gun cycles in live fire. Perhaps it's unsafe with those who really shouldn't be handling any sort of power tool or sharp instrument.
It is also possible to use a pencil to "shoot groups" at home: tape a piece of paper to a vertical surface and draw a small bullseye on it, drop the pencil down the barrel, and stand so the muzzle is about an inch from the paper. The firing pin impact drives the pencil forward, marking the paper with your "group" about 1/2 inch below the bullseye. Obviously, there is some slop between the pencil and the .45 bore, but it's remarkably consistent for all that.