As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, RIGHT ENGINE STARTED TO BACKFIRE AND RUN ROUGH. ENGINE WAS SHUT DOWN AS A PRECAUTIONARY METHOD. UPON TROUBLESHOOTING, FOUND LT MAG BAD. MAG WAS REPLACED WITH A YELLOW TAGGED UNIT. ENGINE WAS GROUND RUN, CHECKED SATISFACTORY. AIRCRAFT WAS RETURNED TO SERVICE.