From what I understand, the only weapons that can be damaged by dry firing are rimfire cartridge guns because the firing pin can over travel and hit the edge of the chamber. I traded my Ruger P93dc for the BUL, I never took out the firing pin on it but being a Ruger, I doubt it can be harmed by anything less than a thermo-nuclear device!
Those Rugers are WAY overbuilt IMHO, which is bad for gun weight, great for longevity.
If you notice, the snap-caps are usually packaged in 5 or 6 packs which make it seem they are geared towards revolvers.
A far as the video, I'm looking to buy my first too. Can't give suggestions now. The main point to my statement about getting a video is that it will provide a tangible benefit for your money , the caps won't.
The video I will be looking for will be a 1911 based beginners guide dealing with proper handling, proper stance, firing for accuracy and a primer on accessories that will benefit the new (or just getting serious) shooter. I will definately post a review for you when I find one that comes close to what I'm looking for.