Looking for options on getting tighter lower/upper fit
I have a M&P15T and its a great rifle, but i want to eliminate the side to side play as much as i can. I know a lot of people use those little red accu wedge or whatever they are called. I was wondering what my other options are. I had heard there was something that replaced the pins and then tightened down with like a allen wrench or something. Thoughts?