The type of bow and all would be helpful, so I'm going to do some constrctive bashing here. Most factory bowstrings are very close to junk. They are not prestretched and will creep gradually over time causing peep rotation, drawlength increase and peak weight increase. Brace height gets shorter and A2A gets longer.Another thing you may notice is serving separation where the strin wraps around the module---another sign of an inferior string.As always I recommend getting a decent set of aftermarket strings and cables and your problem will be cured.

Without seeing the bow, I'd suggest putting some twists in the string. This will help make it stabilize and it may cure the problem. Of course you should respec the bow. You may need to twist the cable to keep the drawlength the same if it fits you well now. I've found many factory strings come with only a few twists in them. Then I order a Wnner's Choice or Prostring and notice that they have about 1 twist per inch of the string's length. I'd have to assume it works as I get zero peep rotation.

I will also caution you about something. If the peep turns precipitously and turns a lot you may have a string that is ready to break, usually under the serving but not always. I had this happen once and it got real ugly. The peep was turning a lot from shot to shot, all of a sudden it let go and I was holding a pile of junk in my left hand.

Anyway, do a search on some of the aftermarket string makers. I'm working with a guy right now that gets some pretty good reviews and the prices are reasonable. As of now I have not shot his strings but plan on getting a set to try them out. You might do the same. His name is Mark Mraz and his phone number is (828)627-2594. He's on this board and over on www.archerytalk.com. Maybe it's worth a try.