just to add to what nine banger said, if you are "measuring" lead it means you are aiming--that's an almost guaranteed miss. Basically aiming of any sort means you are focusing to a degree on the barrel or bead of your gun. When you do that, the bead will appear to be moving faster than the bird becasue it's closer, and your eye will naturally focus on the bead--NOT the bird--becasue that's just how your eyes work, they automatically focus on motion. Focusing on the barrel rather than the target prevents your natural eye-hand coordination from functioning properly, and you will miss. The one, single most fundamental element of shooting a shotgun at flying things is to NEVER AIM. You look at the target and focus on the beak of the target and nothing else. Without breaking your focus, mount the gun and shoot the target. Your natural eye-hand coordination will build-in the lead, but only if you have a HARD focus on the target. In reality there are some other techniques people use and you may need to swing through the target a bit, but you'll hit a LOT more birds doing this than you will by "measuring" or consciously "leading" the bird by checking where the barrel is in relation to the bird becasue that IS "aiming".
