. I've put it into several different firearms with unique calibers starting from 7.sixty two, 9mm, 5.fifty six, ect. Its ran flawlessly in each. I did not have to swap buffers or springs or just about anything. Just flip to third position and he or she's ready to go.. Thanks https://frt-trigger24566.activosblog.com/35124458/getting-my-rarebreed-triggers-to-work