Interarms Virginian Dragoon Sight Problem

No offense intended, but are you sure it's the sights? The group looks roughly centered in the second target with the black bull. The red dot target has the group off to the right but without a scale for size, it's hard to tell how much it's off. Are you shooting off a rest or sandbags? Standard advice here with this sort of issue is to have someone else shoot it from a solid rest and see what their groups look like.

Is it possible you are pulling the pistol to the right? Too much finger on the trigger? "Milking" the grip, i.e., squeezing with the whole hand instead of pressing the trigger? Is this your first single action revolver? The fact that the offset remained even after you moved the rear sight makes me suspicious. Again, these are just suggestions without knowing how much experience you have. If you shoot good groups with another handgun, then I'm off base. But I would look at all factors before I did major surgery on the front sight.

If you confirm that the revolver is in fact off to the right, it may be possible for a gunsmith to turn the barrel slightly to correct. Again, I'd investigate that option before removing the front sight.

Your gun doesn't seem to be grouping too well. Try using a larger diameter target, if you are in fact aiming at that small red sticker. Shooting at a target that's too small makes you hold and try too hard to maintain the sight picture. At 25 yards, a 6" dia. bull is better.

And you might try to getting rid of that rest. Unless its absolutely rock steady, you can probably shoot better without a rest.

It's possible to adjust windage on a revolver by turning the barrel slightly. Clamp the gun between two soft wood blocks in a vise, then clamp two more blocks on the barrel. Use a lot of resin on the barrel blocks and clamp them tightly. Use a wrench to turn the barrel slightly -- and remember the rule: When adjusting the rear sight, chase the target. When adjusting the front sight, chase the bullet.

But I'd do quite a bit more shooting with that gun before I did anything else. It is a truism that you cannot sight in a handgun from a rest -- you can get close, but you still have to make your final decisions based on shooting off-hand.