Soft Face Bolt Question

[JawCrusher]

Had a question about the Soft Face Bolts. I know what the soft material up front does. It's to be gentler on the balls and eliminate role-back. There's also a red dowel looking thing inside the bolt goes down the air passage way. What is the purpose of this part?

I'm asking because the Cobra bolt I have has a straight through design. I'm wondering if this part is for performance.

Any insight would be appreciated.

Thanks in advance.