Had a Uberti Dragoon once that wouldn't bust caps new out the box. Sent it back to the importer who sent it back no fault found - except the barrel wedge wasn't tapped in far enough. Worth checking.
If the wedge isn't in far enough, you can get too big a gap between the cylinder face and barrel. When the hammer falls it pushes the whole cylinder forwards until it's stopped by the barrel. This absorbs the blow of the hammer and results in a mis-fire.
I had no more problems with mis-fires once I got the hang of driving the wedge in the correct amount. A gap of .003" - .005" between cylinder and barrel is about right.
Tight wad
If the wedge isn't in far enough, you can get too big a gap between the cylinder face and barrel. When the hammer falls it pushes the whole cylinder forwards until it's stopped by the barrel. This absorbs the blow of the hammer and results in a mis-fire.
I had no more problems with mis-fires once I got the hang of driving the wedge in the correct amount. A gap of .003" - .005" between cylinder and barrel is about right.
Tight wad