Hillhntr,
I would say that generally, 300 shots will break the bow in. Some will give you a different opinion, but this is average. I bought a 2001 Vortec brand new last year, and to tell you the truth, the string never stretched enough to make a difference. In other words, I have over 5000 shots on my Vortec, and I have never had to re-adjust anything. I have had others tell me that they did have to make slight adjustments though. Hope this helps.