Without snap caps.
Depends on the gun. In the usual series 70/series I type 1911's you're just fine.
Research your pistol.
If you look at the way a firing pin works your putting loads on the pin that its not designed to take.
Instead of the pin itself taking the shock load of stricking the primer, the sholder or body of the firing pin takes the load and all of the load against the inner sholder. And instead of a deceleration caused by the deforming of the pin against the primer the shock load is much greater against the end of the firing pin hole since it stops much faster than when it strikes a primer.
There is nothing for the pin to strike so you get a negative load on the end of the firing pin instead of a positive load.
To make it a little easer, its like stoping your car with your breaks or attaching a steal cable to the bumper of your car and latching the other end to a tree. You get the same job done, stoping the car.
But do you really want to do it.
So when you say recearch your gun, you might want to research a little engineering and shock loads also.
So if you want to dri fire, have fun, but I wont with out snap caps.
I have had a gun come into our shop with a firing pin broken off from dryfiring.
A little wont hurt a gun, but excess is somthing you wont want to do.