Get a "TRU Speed Nok with Peep Aligner". This is a 2 piece nocking point that screws together around your string. There is a tab on the back that your nock hits each time you nock an arrow and it turns your string to same spot each time. I used one for years and loved it. I don't need it on my bow now since I have a very good quality aftermarket string, otherwise it would still be on there.
http://www.cabelas.com/cabelas/en/templates/product/standard-item.jsp?_DARGS=/cabelas/en/common/catalog/item-link.jsp_A&_DAV=MainCatcat21424&id=0004497 413037a&navCount=1&podId=0004497&paren tId=cat600309&navAction=push&catalogCode=Q S&rid=&parentType=index&indexId=cat600 309&hasJS=true
Good luck ... Shockwave