Refining my Revolver technique... for 150' target

[tsafa]

This was a blackpowder-weekend for me. I shot my flintlock rifle on Saturday and my .44 BP Revolver on Sunday.

I normally shoot pistol at targets between 21' and 50'. Since I was able to get 6 inch groupings with my .44 revolver (1858) at 50', I decided to take it over to the rifle range. This revolver has a long 8" barrel that gives it great accuracy. I load up to 32 grains BP which is at the high end for this pistol but I can manage the recoil fine at normal pistol engagement distance.

I set my target at 150' and I found that while I was getting 4" groupings at 50' I was consistently off to the left at 150' by about 12". I normally shoot left about 2 inches at 50 feet unless I make a conscience effort to hook the trigger good and push in with the thumb of my off-hand. When I am mindful of these fine points, I get nice groupings around the center-dot.

At 150' feet... no mater how much I hooked the trigger and pushed in with the thumb of my off-hand, I kept shooting to the left by 12". The question I am considering is... can I do anything to refine my technique and get closer to target at 150'... or is 150' just asking too much for a revolver. I am aware that I could just aim 12" to the right and hit my target but I am looking for a better way if there is one. Any feedback and advice is appreciated.

edit:Something I did not consider is if the fixed sights on the revolver might be off slightly. I shall have to try this with another revolver with a long barrel.