Kaz, I know that sluggish feeling. Different guns feel like that too, MSMC just seems slower in every way. Can't move at same pace with it. Chicom feels peppy, like you're using lightweight. Of course the Scorpion is the COD4 MP5/MW2 Vector/BO MAC10, it just matched up and feels the best in reaction and handling on my end.
Besides the gun, different host do that too. In GW, the game never plays like it does in 6v6. And depending which team has host, the frames play different speeds.