I just absolutely LOVE this question whenever it comes up. The Knee Jerk answer is always NO!!! NEVER!!! NOWAY!!! I spent too many years fixing the guns of the foolish and foolhardy to freely suggest Dry Firing a Percussion Revolver. EXCEPT:
NEVER with guns you intend to shoot in CAS. Should be self explanatory.
NEVER with Nipples in the guns. There are those folks who advocate putting some form of Little Rubber Baby Buggy Bumper on the nipples. Sure. They wear. Bad Joss. Constant impact with the nipples not only ruins the nipples very rapidly but also pounds a nipple side dent in the hammer face. More Bad Joss.
First you need a "Beater." Same make and model you normally shoot. Usually you can find one someone has screwed up by dry firing and get it for pennies. Make it feel like your match gun(s). Take the OEM nipples out and throw them away. Or just pound the hammer and nipples into junque. It's a "beater" remember?? If you dry fire your match guns, you going to need someone like ME!! Not me because I'm retired ... remember?? Someone like me, who isn't retired and understands Cap Guns. When you visit this person, be sure and take your pay cheque with you. The person will want the pay cheque. If you continue to dry fire your match guns, plan on several visits and lots of pay cheques.
Also, if you watch for the "specials" at the Big Box stores, you can often pick up a new gun at beater prices. Oh, forgot, eventually, the hammer in the beater is going to break at the stress riser. Just buy a new hammer and continue to pound it.