Lead shot has a number of different uses. Most commonly, lead shot is used to tighten the line under the float to get your particular float to stand correctly. If you have a float that says, for example, 1.5g, you need hail that reaches the same weight for the float to stand perfectly. If you fish with the lifting method instead, you want to overlead the float. So if you want to fish with the same float with the lifting method, you need hail to a weight that exceeds 1.5g. Another option is to put a lead shot on your carp rig to lead down your Pop-Up so it doesn't fish too high in the water. Choose from different weights to suit your purpose.