Just a couple of thoughts on the missfires:
1. Maybe there was too much oil in the nipples (if you didn't cap-off first).
2. Maybe caps got stuck on the surface of the hammer or as in my case, the surface that the hammer falls on to. With my Colt Walker, I sometimes have a slight accumulation of fired caps get onto the channel where the hammer drops BEFORE it even reaches the nipples. This causes extremely light hits on the caps. On a second go-around with the wheelgun, the caps fire fine. If this is the case with the Ruger, both your caps and your nipples could be just fine.
3. If the caps are firing and the load isn't it could be just dirty nipples. When I clean my gun I always use Butch's BP Boreshine and I take off the nipples and soak them in the solution. Then I use a nipple pick to make sure everything is O-K. I don't use oil inside the nipples...never have! But I do oil the threads of the nipples as I re-install them into the revolver.
For the Walker I use CCI #11 Magnum caps. For the trade rifles I use Remington #11 caps. Never had a traceable missfire with either...always my fault (dry-balled once) :redface: .
Hope this helps, Dave