Neil you surprise me with the size of foresight elements that you usually use! I used to think that I was using a relativly small ring when using a minimum of 3.9mm. I used to find that I needed to use the 3.9 at 25x as otherwise I got intrusion from the other aiming marks. I used to go as far as 4.5mm standing, but talking to some of the better scoring younger shooters it seems that 4.2mm is about average for prone these days, and 5 and even bigger is being used. I did once shoot without an element at 1000 yards at Bisley as it was still a bit misty.

Alan