Actually, I broke two different Ruger revolvers - a .44 Redhawk and a .45LC Blackhawk - by dry-firing them on a daily basis. Both times, it was the cheesy-looking cast bar that slides up as the hammer falls (the "transfer bar"?) that jammed up the gun. Ruger repaired both of them, but I never did subject my guns to that amount of dry-firing again. Ironically, my S&W Model 29 (1998 vintage) still broke anyway after only a small amount of dry-firing - one day the firing pin assembly on the hammer just chipped off. I have read though that this may have been caused by some weak-steeled hammers S&W was using at the time.