The number is not the length, so.il.hntr. That's the spine, or stiffness, classification for the arrow. It's supposed to work on bows ranging from 50-60 pounds of draw weight at a given arrow length where the 6075's would work on bows from 60-75 pounds at a given arrow length. That's an overly simplistic explanation though, not including draw length, cam type, release type (fingers vs mechanical) or point weight. Those are all variables that effect how stiff your arrows need to be.

If your arrows aren't stiff enough, they won't ever shoot worth a whatever-you-said. For a release shooter, it's much better to have arrows too stiff for your setup than too limp. But it's always best to properly match your arrow spine to the bow.