In a decision that may become a model for the nation, a federal judge here ruled that gun restrictions imposed by the Wilmington Housing Authority on its residents are constitutional. The housing authority’s policy of prohibiting residents from openly carrying firearms in “common areas” of public housing buildings is reasonable and does not unduly restrict residents’ Second Amendment right to own and possess a gun, U.S. District Judge Leonard P. Stark wrote in a 42-page opinion. The original lawsuit was filed June 1, 2010. A few weeks later, a landmark U.S. Supreme Court ruling found that state and local governments couldn’t impose blanket bans on gun ownership. Following that ruling, the housing authority dropped its blanket ban on firearms in September 2010 and instead adopted the restrictions on guns in common areas. But the plaintiffs, backed by the NRA, did not drop their lawsuit after the housing authority made changes, insisting that the new restrictions also were unconstitutional. The Brady Center to Prevent Gun Violence filed a friend-of-the-court brief supporting the housing authority.