My Tubbs precision flat coil buffer springs are a bit harder to pull back then the std setup.I actually have never played with an AR much but like I said it seems much harder to pull back than it should. I really dont know much about these I have never owned one or taken one apart yet Im guessing that will happen soon. This is an off the shelf rifle so im not sure what it has in or on it as far as parts. I will post a pic here in a minute.
But they work lots more gooder, so I roll with it.