Mike,

I had been having a heckofatime getting my bh's tuned.

I finally did a bare shaft test last week and discovered that my spine is weak (400 Beman BlackMax, 27.5", 66lb SBXT).

With my old bow, I was shooting Axis ST 400's at 60 lbs and the bare shaft test told me I was nearly spot on for spine.

I've also noticed that the bemans are not nearly as durable as the Eastons although they "seem" to be the same shaft, I don't think they are! Perhaps they're also a bit weaker in the spine department?

Maybe you have a weak spine?