hit the (broad) side of a barn
slang To hit a target that is difficult to miss. Almost always used in the negative to mean that one has very bad aim. Boy, you can't hit the broad side of a barn—the net is over here, you know! These guys haven't made a single basket in the last 10 minutes—they just can't hit the side of a barn right now.
hit the (broad) side of a barn
Fig. to hit an easy target. (Usually negative.) He can't park that car! He can't hit the broad side of a barn, let alone that parking place. He's a lousy shot. He can't hit the side of a barn.