A couple of "watch out's" with plated shot.
As I am sure everyone will agree, not all lead shot is the same, subsequently not all plated shot is the same.
Much of what you buy as copper plated is really only copper washed, which doesn't do much but make the shot more expensive.
The plating does not make the shot harder. The hardness of the shot is dependent on the antimony percentage of the base lead, just like it is for hard vs. chilled shot.
If they started with chilled shot, you will have nickel or copper plating on soft lead shot.
It may be worthwhile to test the hardness of the shot with some contraption like Neil Winston uses, just to compare the shot side by side.
Really screaming fast loads with chilled shot may result in really bad patterns. Does it matter? Well, to the pheasant, it probably does.
Me?
If I make hunting loads, I'll just use number 4 or number 5 magnum lead shot. It kills them dead enough.