I think I understand what is happening, the bar is being pushed too far, then the chuck closes on a long piece sticking way too far out of the chuck when it closes, and the turret is colliding with the bar, right? The easiest way to fix this, is to program a stop in the turret. That way the bar can not come out too far. I do not think there is a parameter change. Maybe I'm wrong. It wouldn't be the first time.
I have never used a feeder that would feed lengths ---only feed against a stop. I would think that it would be a bar feeder issue not a machine issue. I only say that because it would be some pretty intensive variable programming to get that to happen at the control.