I use CLP, the 'sproing' is indeed a thing with a fixed stock, it acts like an echo chamber.
Sorry for dredging up this old thread, but I am in the process of my first AR build, so I consulted MidwayUSA. Larry Potterfield--in his lower assembly build video--demonstrates using liberal "lithium grease" on the buffer spring and buffer. He's kind of the Dean of Gunsmithing, so his advice is important. What are your thoughts?
the Dean of Gunsmithing