I agree that percussion caps can be a problem, on any firearm, not just revolvers.
However, a few tips:
As I was telling someone else on here, take your nipples out and polish them. This will allow the spent caps to come off easier.
Also, if you are using Remington or CCI caps, they are a part of the problem. Get some RWS (Dynamit Nobel) caps, with the pleated skirt. These will go on, and come off, much easier.
“... take your nipples out and polish them. This will allow the spent caps to come off easier...” [G-Bear, post 30]
Nipple (cone) sizes and cap sizes vary quite a bit. Nipples that supposedly require a particular cap number sometimes won’t work with that cap number (they can be too loose or too tight); other times, caps of a given number from one cap-maker will work, while those of the same number from a different cap-maker will not.
Some authorities recommend polishing the cone, as you have suggested; still other counsel machining or filing, to get oversize cones down to a usable diameter. It’s probably less bother to try different cap numbers, or caps from a different maker, before going so far.
Pinching a larger cap to fit more tightly on an undersize nipple is a common technique.
I’d be reluctant to polish nipple cones, especially on a revolver. The smoother they are, the greater the likelihood that the firing of one cap may blow unfired caps right off the cones of nearby chambers. More than an annoyance: flame and sparks could enter the unfired chamber and set off the charge. Grease or sealing wads are recommended for the fronts of loaded chambers, but little attention has been paid to the rear end. One can drip melted candle wax into the cap recess of an already-capped chamber. But there is a risk that the cap’s charge will be contaminated and rendered inert.
Haven’t had the privilege of seeing RWS caps. Skirting to counteract an inexact fit on nipple cones is a good idea. At least, as long as one can afford any.
The Tap-O-Cap is a less costly alternative. I understand it’s now out of production, but one might find some on the used equipment market. Dixie Gun Works used to sell it: a punch and die set that forms pleated-skirt caps from the wall of an aluminum beverage can. You punch out caps from half-inch strips of aluminum, then punch out the charge spots from rolls of paper caps for toy guns. Using a small dowel with a wetted tip, or the end of a Q-tip from which the cotton fuzz has been removed, you pick up a charge spot and press-fit it into the underside of the cap. The pleats allow perfect fit and easy application onto a variety of nipple cones; two or three charge spots (or more) can be inserted, for best results. Caps thus assembled aren’t moisture-proof, unlike commercial caps. The charge spots usually stay where you put them, inside the cap.
Without a doubt, a very fussy and time-consuming task, but the cost of materials is very low.