ORIGINAL: ironranger
Bowtech, there may be some other previous posts on this out there if you search and I'm sure there are many different ways to do it correctly. What I did was start at about 15 yards so I'd get a real tight pattern. I used 2 3/4" number 5 pheasants loads for the initial shots at that range because of price and also recoil. Those 3.5" loads knock your teeth loose and are about $2.40 per shell as well. I was shooting low at that range so I moved the aim point in the down direction which actually brings the impact point up. then tested again and had a good pattern there. Then I moved out to 40 yards and switched to 3.5" Winchester Xtended range shells. Patterned good but seemed to be a little to the left so I moved aim point to the left which brings impact back to the right. At that point I was getting a uniform pattern at 40 yards. Then I went back to 20 yards and fired one more shots just to make sure I was good at that distance. Looked good so I left it at that. I skipped shooting at 30 yards for the sake of saving shells!!
I just sighted my Ithaca Mod 37 Turkeyslayer with a Bushnell Trophy Red dot scope in. I started at 20 yds with # 7 1/2 target loads to set the evelation & windage. I had to move the evelation about 10 clicks and I was center cut. I then switched to Rem 3" #5 Hevi-shot and patterned it using a NWTF turkey target and got the following results. At 10 yds over 40 pellets and a hole the size of a golf ball in the kill zone, 20 yds 77 pellets, 30 yds 24 pellets, 40 yds 14 pellets. I guess I'm good to go.