If they do have a rapid-fire restriction, an imperfect substitute, just to develop the muscle memory, is to load a dummy under or after the live round and click away.
The main practice element there is the recovery from the first recoil... at least, that's the way I see it.
Hadda do that at one range a long time ago. I still do it once in a while just to save ammo when "refreshing" with a long-unused gun. I load dummy, live, dummy, live, dummy, live, to the mag or cylinder capacity, making sure the last round (first one in the mag) is a dummy.
For them double-action revolvolatin' guns you have to think about it a second or two more, and remember the direction of cylinder rotation*. First time I did this with a 7-rd revolvolator it confused me, but it worked out OK.
Terry, 230RN
* Smiths rotate counterclockwise from the rear of the gun, Colts rotate clockwise. Rugers go counterclockwise, too.