galting gun good or not?

It's a camping gun. When you are running & gunning, it is perhaps the single worst gun to pick up from the crate because you're going to have mutants on your tail and the weight and warm up of the gun will finish you off. It's also only good if you have a partner with a regular weapon who can hold off the swarm of mutants long enough for you to get through the gatling's warm up period. With all that being said, it is an excellent camping tool to have at your disposal.