I have had 3 outings now with the 6x18x40 fine duplex, it has responded just as I had hoped. IMO this is just about a perfect match for load work, small varmints and deer hunting. Now the fine duplex might get a little hard to see at dusk.
I have been very surprised by the optical quality and resolution. On each outing I have also had along a March 2.2x25x42 that is just about the perfect scope for ME an my needs. But the Mark 4 in decent light appears to be a lot of scope for the money. I twisted on the erector pretty hard and while not exactly perfect it is very workable.
I played with the AO some and it does its job and takes care of any parallax issue's. I now own 3 of these scopes, 2 of the 3x9 and this 6x18 and I think I will be keeping them around.
