By Brendan Pierson (Reuters) – Mass school shootings, like the one that killed 21 people last week in an Uvalde, Texas elementary school, have frequently led to litigation against school officials, law enforcement, perpetrators’ families and gun manufacturers. Outcomes of past cases have varied widely, with some cases dismissed on legal grounds early in litigation and others reaching settlement. No cases have so far been filed over the Uvalde shooting. Here is some of the notable litigation filed in the wake of shootings: Columbine High School, Columbine, Colorado, 1999 – Students Eric Harris …