Wait, you can't have it both ways. If HS #6 hits like lead #5, then HS must be heavier than lead and a 1 1/2 ounce load of HS must have fewer shot in it than a 1 1/2 ounce load of lead, resulting in less density of pattern. Let's not split hairs. Any good patterning heavy load of fairly small shot, lead or HS, will kill a turkey quite dead. Nitro Cartridge says that one is heavier than the other, some posters say the opposite, so they must be pretty close. Another poster says HS comes in several weights. I am willing to admit that either will penetrate the head of a turkey when propelled at 1100 FPS to 1250 FPS. If the shot is going through the head, why increase the velocity? Add shot load instead. That's why I prefer the 3 ounce Nitro Cartridge 1130 FPS load of #6 lead. It has the most shot, the thickest pattern, and probably the heaviest #6 shot available. If I were to want to shoot at a turkey's head at 60 yards, I would not think of another option.
