In the 50s, long before I started hand loading, the CIL ammunition rep in our region Dunc Morrison, whose son later headed up Ducks Unlimited, straightened me out on what you say of changes from charge, shot and wads.
The expensive blue Imperial shells were preferred at the time by serious duck hunters. The green Maxum came next, followed by the low-base red Canuck. Dunc said "You're a decoy guy, try these," handing me six boxes of Canucks.
I demurred, saying they're fine for partridge but not ducks. He said the lighter loads provided better patterns, fewer crushed flyers, an all-round good shell for anything over decoys. I never looked back.
