. I've put it into several distinctive firearms with unique calibers starting from 7.sixty two, 9mm, 5.56, ect. Its ran flawlessly in each one. I did not have to swap buffers or springs or anything at all. Just flip to 3rd placement and she or he's all set to go.. https://donovanrkdmw.nizarblog.com/36471780/frt-triggers-things-to-know-before-you-buy