the reply i got from alan
You need a variation for a ".357 Muzzle Loading Revolver".
The standard barrel Armscor will produce 2 1/2" group at 25m, The Match barrel version about 1". I have not tried it at longer ranges though I do not see why they should not shoot at 50m quite well.
i have shot the taurus 357 good fun but do they have probs with there barrell jamming up ???