I have a loaded M1A with the VLTOR rail system on it. I put a Nikon Monarch in Warne rings on it and shot it a while.
I have since taken the scope off and only shoot with the irons. Those sights are amazing.
I shoot the 300 popper with mine and if you are careful with your follow through, you can see the bullet "trace" just before you see the popper move.
I have since put that scope on a CZ 452 rifle. That rifle is pretty amazing too.