Carp , if you would have had a sharpie it would have helped as the same arrow with a bad nock would repeatedly shoot bad . Nocks dont have to be broken to be bad , they wear out , sometime fast , even the fletching glue we use can weak'n them . If I have an arrow that flys bad and its straight , and the fletchings look good , Ill change the nock and that usealy brings it right in a group with my arrows that are flying good . Nocks are my petpeeve as they are something we tend to forget about , but they wear out and replaceing them can have drastic effects for the good . Too tight a nock fit is another problem unto itself .