the biggest difference between revolver nipples and rifle nipples is that revolvers are very fussy about how long the nipples are; too long and you cannot revolve the cylinder, too short and the hammer does not strike the cap hard enough. I think the big difference in nipple wrenches is that the diameter of the wrench at the business end is smaller in order for it to fit inside the metal fins that separate the nipples. The one exception that I can think of is that Ruger uses a hexagonal socket type wrench and has a hexagonal base on its nipples
cheers mooncoon