Enfield striker

I have an Enfield No. 5. I tried to disassemble the bolt, with the usual two prong tool. The striker pin turns easily with the tool. The striker tip is flush with the top of the bolt body, and the screw is flush with the bolt body's bottom. But there it sits, turning and turning but not releasing the striker. Any ideas on what I need to do to unscrew the last 1/4 inch?

Sounds like the thread of the striker is burred up slightly and is fouling the hole at the rear of the bolt body. Just push the bloody thing out of the bolt body!