If you can name one, they used it. From the simplest of blackpowder weapons to the .22 short, the Gatling gun and the Henry (and Spencer) lever actions.
They cast bullets in huge bulk amounts. They even had an extruded method. One story says the methods were so secret that info wasn't released until the early 1900's.
The most common "improvement" of the era was casting a bullet with a heel skirt that only expanded upon ignition. This allowed a reload to be rammed home down a dirty bore with greater ease. Even bullets shapes changed, and conical rounds were used.
As for revolvers, take your pick. There were revolvers with top straps, some without, some made of iron, some of brass. There were side hammers and a monstrous LeMat revolver that not only fired bullets, but a shot shell, as well.
This is truly a topic where you can pick your specialty, and study it for a lifetime.