Tap the retainer pins out. Soak it with PB Blaster or the like overnight. Use a large brass hammer (softer, might mark the metal, but will give first and not destroy your parts. )I turned my barrel (had to pull it to fit my lathe), and set the sight back. Threaded 14x1LH, plenty of metal to do this. Also turned bbl down from the gas port (same OD) back, and dremeled out a Romy lower handguard retainer, so I could put on a real handguard.Plus the obvoius other mdos, can't help it...