You ****ed up your bolt. Grease based lubricants such as 55, 33, Hater, and anything else are going to swell delrin. Aside from your ****ed up bolt you may try adjusting your regs. LPR should be at 80, and the HPR with about 2 threads showing on the set screw to start. Then the HPR should be set to whatever gets you 280fps.
If I seem like an ******* sorry. I'm feeling *****y.