BLOOMBERG RETURNS. We reported in last week’s New Hampshire Primary Source that former New York City Mayor Michael Bloomberg is planning a return visit to New Hampshire before the end of the month.We’ve now learned that the visit will be on Tuesday, Jan. 29, with details of public events expected soon.Bloomberg, who re-registered as a Democrat last fall, has not yet decided whether to run for president, and his visit to the first-primary state, which is expected to include private meetings, will go a long way in helping him make the decision.Bloomberg was most recently in the state pushing his pro-gun control agenda last October, meeting and holding an event with Nashua Mayor Jim Donchess and six candidates for the New Hampshire House.Bloomberg has been a leading gun control advocate since his time as mayor. He founded Mayors Against Illegal Guns in 2006 and was deeply involved in the organizations founded after the shootings at the Sandy Hook Elementary school -- Everytown for Gun Safety and Moms Demand Action.Bloomberg, a Boston native, has noted that he was a Democrat for most of his life before leaving the party in 2001 to run for New York mayor as a Republican. He left the GOP and became an independent in 2007 and was elected to his third term as mayor in 2009 while affiliated with neither political party.Last October, Bloomberg announced that he was re-registering as a Democrat.Watch for more New Hampshire political news in our full Primary Source column, which will publish on WMUR.com early Thursday morning.