Good comments above.
Remember that every type of wad has been designed for maximum performance with the hull type, powder, and shot charge.
The wad is a shot cup, shot buffer, gas seal between the powder and shot, and a gas seal for the shot as it leaves the barrel. It was the plastic wad that made the "forcing cone" less of a necessity.
Once the wad leaves the barrel, the open end slows the wad so it doesn't "push" the shot and deform the pattern. A good wad for clay shooting will only fly about 20 yards before it slows and falls to the ground. Hastings Barrels went as far as straight rifling or grooving their barrels to further slow the wad.
Regards,
Buckmark