Got poor results with 100gr magnums and the Excal bolt with 5" vanes. Poor graouping. Swithced to 100 gr regulars Slicks and group shrunk. Couldn't have guessed that 1/8' width difference would have mattered, but it did. Can't be weight forward issue, since weight is the same. Magnums fly well with Carbon Express and 4" vanes with another bow. The Excal bolts are about 70 grains lighter overall, however. Since it's a flat nock/moon nock difference, I havn't tried them the other way to determine if it's the bow. Must be the big vanes and bigger broadhead not compatiible.