By Riley Gutiérrez McDermid After mass shootings, a lot of investors are saying enough if enough. Americans outraged and desolated by the last two weeks of mass shootings have begun taking action to unwind any personal investment they may have in companies that make guns or ammunition. The mass shootings in Uvalde, Texas, and Buffalo, N.Y., are the most recent examples of horrific violence carried out with virtual impunity by a young man whom authorities had failed to flag well ahead of time. Now, U.S. investors who have felt helpless in the past are finding ways to yank their investment out o…