So first off, have you checked your revolver for proper timing? Most shooters I've met don't bother or don't know how. With slight mis-timing, lead gets sheared and it'll spit regardless of the barrel cylinder gap. When/if it gets further out of time, it becomes a profoundly dangerous problem especially with the higher pressure cartridges.
For those who don't know how to check a revolver for proper timing, I'll line it out.
1) Check to ensure the gun is unloaded
2) Repeat step one!
3) Close the loading window (for single actions), close the cylinder into the frame (for double actions).
4) Gently rotate the cylinder until it latches securely.
4.5) Point the muzzle at an appropriate backstop.
5) SLOWLY cock the hammer taking great care not to touch the cylinder as it rotates. As soon as the hammer reaches full cock gently grasp the cylinder and rotate it in the direction of normal cylinder rotation. If there's ANY movement before the cylinder bolt clicks home, your gun is out of timing.
6) Repeat step five for each chamber in the cylinder.
7) Now repeat step five only cocking the hammer quickly. Most of the time the gun that passes with the test when worked slowly will pass when worked fast but it's happened to me.
That's pretty much it. Some folks worry about measuring tolerances and dimensions but I've found that loose tolerances that don't impact timing, generally reduce accuracy but don't create a safety risk.
