If your just shooting for fun it isn't that big of a deal. 1 1/8 oz or 1 ounce verses 7/8 ounce of shot doesn't always show major differences.

However if you are in a major competition there are other things to consider.The one or two targets you pick up with the larger load can mean the difference between winning or finishing with the rest of the pack.

Further the difference in the dynamics of the guns arenormally worlds apart.A hitch in your swing in a tournament is far more detrimental to ones score than an 1/8 of an ounce of shot.That is why you see 20 gauges tubes put in 12 gauge barrels (normally done in skeet but it is also done in sporting clays)so the shooters swing (and sight plane) are not affected.