They make alot of different diameter servings.What are you string spec's now,what type of string and serving are you using now? I have servings likie .017,.018,.019,.021,.024,.025 and .026 and there a few more different diameters.There is also what type of nocks are you shooting now?If you are using the standard push-in nock like on GT.The Easton 3D Super nock,they have the largest and deepest throat of those types of nocks.These nocks fit uni-bushings in aluminum and most standard size carbons with a .246 ID.