I get the same thing. Do you lock your left arm or is it slightly bent? Mine is slightly bent, but I don't know if thats proper. I taught myself how to shoot the bow so I'm probably doing all kinds of things improperly. Normally, my eye sight starts to get a little blurry by about the same time my arm gets tired. Someone suggested a larger peep sight for that problem so I had that added with a new string and I'm picking it up today.