My order of cap sizes from smallest to largest goes like this: RWS #55, CCI#10, CCI#11, RWS#1075, Rem#10, Rem#11. Half of my guns will take the CCI#11, half will take the RWS#1075 but ALL of them will take the Rem#10 or I buy the TOW SS, Uncle Mikes SS replacement nipples to make them fit. The CCI#11s are the closest to the Rem#10 just not as forgiving as to nipple fit. The REms are pre split and of thinner copper so they swell upon seating and grab a greater variety of nipple shank sizes. The CCIs are not pre split and are harder to seat but fit quite a few different guns and are more available.
With over 15 perCUSSIN' revolvers, I've been called the Imelda Marcos of cap & ball.
SASS#3302 (Life), SASS Regulator, NRA (Life), DGB#129
Wolverton Mtn. Peacekeepers (WA), former Orygun Cowboy (Ranger, Posse from Hell)