For a revolver to shoot accurately there must be a correct size relationship between the projectile, the cylinder throats, and the groove diameter of the barrel. Generally the projectile should be a neat fit to the cylinder throat and 1-2 thou larger than the groove diameter. Ruger are notorious for ignoring this, especially in the .454 models. This is a bigger problem with lead, but still impacts on jacketed, especially at a distance.

Have you measured your cylinder throat diameter. If they are too small a good smith can ream them to size. If they are too large then all you can do is go to get a custom mould and cast your own projectiles.

If all dimensions are OK, then it comes down to personal technique which is easily fixed by practice.