shell question

[backwoods7]

Was curious about something and thought maybe y'all could help.

Comparing a couple of Winchester loads. Ones the superX(silver box) the others the supreme(black box) both are 3" #4 and cost roughly the same. $11 or so. Is there any difference? I've used both in the past both seem to shoot well but this question for some reason has bugged me.

 

[darn2ten]

The super x is a 1 7/8 oz. load. The old supremes were the black shells are the 1300 fps. high velocity load at 1 3/4 oz. The red double x shell is the 2 oz. load. They're all copper plated.