I wne to the Wake County range today to sight in my ar. I am having a focus problem. I noticed that every time I mounted the rifle I had to refocus it. I wear progressive bifocals. Has anybody had problems retaining focus with them? It is hard to get a consistant shot when I cant seem to keep the target focused while looking at it. On a side note I dont seem to have this problem shooting my handguns with iron sights. Not that I have noticed anyways. Any help would be apreciated.