Jay, You must be using 1oz loads and it would appear your gun is tightly choked. I don't recall offhand how many #8 pellets are in a 1oz load.
I don't worry about choke when shooting as I just like to get out and swing a gun. I do 90% of my SC shooting skeet choked guns however from 12-28 ga. I have been shootin a D3 hammer gun lately thats choked .015 &.025 as I remember which is mod and a tight mod. I have also used a 16 with full and fuller choke constriction. I think the tighter chokes will make you a better shot in the long run as there isn't the room for error.
Shoot your 20 regardless of choke and have fun. I'll be taking the VHE 28 skeet/skeet out for a round Sunday to limber up for the Grouse opener in a couple of weeks. I only have #9's for her which arn't the best but so what. Its time she saw some action