NONE ,That is unless they have both , such as acc's , or beman matrix . I have used several manufactures of carbon shafts , none have been even close to the consistancy of alluminum , not close at all . The best carbons I ever used were ,carbon express teriminators , and they lost their spine after about 200-300 shots . Ive never had an alluminum lose its spine that I could tell , they will group after years of use .