Just so people know, if your spine is a bit weak or a bit strong, you can still tune the arrow to shoot a broadhead well, but you will need to adjust center shot accordingly. The problem arises when some are a bit weak and some are a tad stiff. Now, you have arrows going left and right. Center shot adjustment has no positive effect on both types at the same time. This is why I choose to shoot all my arrows a bit stiff. Spine tolerances are not yet good enough on most carbons to try and hit it on the nose.