Or does shot stay level between 20 and 40 yards. I will be sighting in my shotgun tomorrow and want to figure on where to set my sights. Right now, I have 2 oz., 3 inch 6 shot in my Mossberg 9200 with a newly installed undertaker (copper and lead coated shot only) .665 and truglow sights.

I have killed two birds called into me by a buddy. One was at around 30 yards, the other about 40. The 40 yarder wasn't hit great, but didn't go anywhere either. Anyway, I was told if I put an extended choke tube in instead of my full choke, I can increase the range, or at least put more shot in the target at 40 than without it. But if I put the choke tube on, I'd need glow sights for increased accuracy because the shot would be so tight at 20 yards, I might now miss a bird at that distance I would have taken without the undertaker. So I went out and got the choke tube and sights, and want to sight it in. I'm wondering if it was worth all that trouble/money, especially considering how iffy it is to get a good combination of choke tube/shot!!!