Do a search under my name to locate a piece I wrote, "How to properly load a cap and ball revolver." Or a title similar to that.
Anyway, the gist (based on my experiences since 1970) is:
1. Black powder is more accurate than other powders. In the Walker, use FFFG or FFG grade. Never use smokeless powder, regardless of what you read or some jackleg tells you.
2. Soak felt wads --- either home-punched or sold by Ox-Yoke as Wonder Wads --- in a homemade lubricant composed of 1 part canning paraffin, 1 part mutton tallow and 1/2 part beeswax. The paraffin is useful because it stiffens the wad and helps it scrape out fouling.
3. Use a powder charge that will leave just enough room for the ball and wad to be seated.
4. Use a ball larger than recommended. I would suggest the Speer .457 inch ball. Conical bullets are never as accurate as the ball.
5. The use of a well-lubricated wad usually eliminates the need for lubricant over the ball, except when humidity is very low and the temperature is high. Here in the Utah desert I start doing it when temperatures reach 100 and humidity is 6 percent or lower.
However, with the greater amount of powder used in the Walker, more lubricant may be needed. Perhaps two wads twixt ball and powder would be useful. Or, you can simply put lubricant over the ball even when using the wad.
6. Seat the wad firmly on the powder, as a separate action.
7. Seat the ball firmly on the seated wad, as a separate action. Doing these separately is easier, lessens strain on the rammer, and gives you a better feel for how much force you're applying.
Also, should you forget to charge a chamber, it's much easier to remove a felt wad than a stuck ball.
8. Upon receiving a new gun, run numerous tight patches liberaly coated with JB Bore Compound or Iosso Bore Cleaner (in the tube) up and down the barrel. I usually do this with at least a dozen patches, working the patch back and forth until wear makes it loose. Then start with another patch.
This will smooth your barrel considerably. You can get the same effect by firing, but it would take perhaps 1,000 or more balls. An hour of this smoothing treatment will bring out your revolver's best accuracy right away.
9. Ensure the wedge is tight in a Colt. Use a nylon or hard rubber faced hammer to tap it in. Start with a clean revolver. Tap the wedge in until the cylinder begins to drag a bit when rotated. Then back the wedge out with light taps until the cylinder turns unhindered again. This is the Colt "sweet spot" as it were.
10. Use eye and hearing protection.
11. Buy a revolver loading stand, that holds the revolver upright. I'm not sure if a Walker will fit in those commercially made. If not, you'll have to make your own. This stand keeps the revolver pointed safely straight up when loaded, should you suddenly need to cease firing, but most importantly it makes it easier to seat wads and balls. Also, you get a better feel for how much force you're applying when you use a revolver stand.
Try to apply the same force to each wad and ball. Consistency significantly helps accuracy in cap and ball revolvers.
12. If you get groups at 25 yards of 2 inches or less, don't be surprised! Cap and ball revolvers can be amazingly accurate if loaded properly. All of my revolvers can usually put their lead balls into a 3-inch circle at 25 yards from a benchrest. They are undoubtedly capable of better, but those iron and brass fixed sights of the Remington and Colt designs are not conducive to target shooting.
