Yep, check the string nocks for any rough or sharp edges. Get some really fine grit sandpaper and round off any thin, sharp or rough spots. My 3D rigs pretty much stay strung from early Spring until late Summer andthey've never had a problem with strings breaking. The only time it's been an issue was when there were rough, sharp edges in the string nocks. What year model is your x200? The reason Iask is that pre-2008 x200'saren'tdesigned for low stretch materials.For 2008, Martin/Howatt started reinforcing the tips for low stretch materials, which have much better abrasion resitance than dacron. If it's a newer model bow, slap alow stretchmaterial string on it.