Churchill,
A big difference is apparent when you switch from lead to steel shot. When the non-toxic shot rules were first implemented, many shooters were disappointed by the performance of steel shot in 2 3/4-inch shells. That's one reason the 3 and 3 1/2-inch shells were developed -- to hold a boat load of steel shot. With the development high density non-toxic shot, the steel shot problem became almost moot. Typically the high density non-toxic performs close to nasty old lead shot in the same size hull.
The down side is cost. The high density non-toxic loads cost much more than steel.
MidwayUSA.com lists Federal steel shot at $17 for a box of 25, or 68¢ per shell. They also have Federal high density at $31 for a box of 10, or $3.10 per shell. That's a 455% difference!
