How were you holding your front sight on the target? Some folks not used to open sights try to center the front post over the center of the bull...effectively covering the target. No go. You should be using the very top edge of the front post/sight as a fine aim point ...I use actually the bottom edge of the bull for a fine target. Aim small, miss small. It takes practice, and alot of folks who mainly use scopes have difficulty sighting open sited guns in because of this. You can do much better with the same technique with aperture sights. Also, can the front site be drifted? Rather than moving the rear sight to extremes, the front can sometimes be adjust too. Are you shooting from a steady rest? Good light? Lots of factors.