I load ten rounds and shoot three groups. Last being four shots. Just using three shots has never worked for me. Some times I have a flyer or move or do some thing dumb and mess up the group. When I get to the third string I have a good idea if it's going to work or not. The four rounds tells the tail. I am not saying this is the way to do it. It is just the way I do it. It works for me.