As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN CRUISE AT FL 250, PROPELLER RPM WAS TO 1200 AND OIL PRESSURE TO ZERO. ENGINE WAS FEATHERED AND SHUT DOWN AND A SAFE LANDING WAS MADE. INVESTIGATION REVEALED PROPELLER SHAFT SEAL HAD COME LOOSE AND WAS LOOSE ON SHAFT. SUSPECT BREATHER SYSTEM HAD FROZEN AND CAUSED CRANKCASE PRESSURE RESULTING IN SEAL BEING DISLODGED. BREATHER SYSTEM WAS INSPECTED AND CLEANED. NEW SEAL WAS INSTALLED AND OIL FILTER WAS CHECKED AND FOUND OK.