How well does bronze conduct electricity?

It is a moderately good conductor, but not great. If you rate pure copper at 100%, then regular annealed copper wire rates an 85%, various aluminum alloys are between 50 an 60%, commercial annealed bronze rates a 44%, brass about 32%, and zinc about 29%. There are several different alloys of bronze, by the way, including phosphor bronze. Each has a different conductivity, so the above is rule-of-thumb info, not exact.