My Pennsylvania fowler (Chambers) has a tapered octagon to round barrel. At the wedding band, I pull the front silver sight down until I can just see the tip of it on the wedding band, place the front sight on the centre of the target and let 'er rip. Works for me. For distances further than 50, I see more sight above the barrel, and for 100 yards, for example, I see as much barrel as front sight above the barrel, still holding the front sight in the centre of the target. That's with 86 gr. FFg GOEX .020" patch and .600 ball.