I take it you are referring to informally shooting clay pigeons rather than the actual game of Skeet. The layout of a Skeet field puts the targets in the 21 yard range. That combination should actually work fairly well, but at that closer range you may want a cylinder choke instead. If you are shooting real Skeet, Skeet is the choke to have. While I would prefer 8s, I have been shooting 7-1/2s lately because they were what WalMart had on sale in both 12 and 20 gauge . When I miss I can blame the shells, but inside I know it's me. When I am on the bird, they break.
What could have happened... did.