good question! hopefully someone here can give both of us insight to this. i can say though that i cock the hammer when i dry fire, and have done it for years. there seems to be no effect on my pistols. i wouldn't think it would hurt anything, but i'm more than interested to see what kind of debate this will bring
russel the cop
CHANCE FAVORS THE PREPARED MIND....
Dry fire to your hearts' content boys! No harm done by cocking the hammer either.
Just remember not to let the slide slam home on an empty chamber if you chose to rack the slide to get the hammer cocked - this is hard on the sear as it gets knocked around as the slide slams shut. Slow the slide by hand as you release it.
While I have confidence that dry firing is pretty safe for a 1911, I use snap caps anyway. Some handgun manufacturers, such as Beretta, say not to dry fire without snap caps, while others don't address the issue or seem to say that dry firing is ok. Everybody's got an opinion on this, but I figure if I always use snap caps, I'll always be right. I've never heard anyone say that dry firing with snap caps could have any negative effect.
Ditto on what shane said about not letting the slide slam foreward on an empty chamber. One more reason to use snap caps.