I ran a Buckridge 8-32x42 for a while and loved it. For my shooting it was just a little too much scope. I went with a Bushnell 6-24x50 and it seems to work out real well....But I might switch back but I like the larger field of view on the 50AO. I will think you will find the 40 objective a little restrictive on varmint hunting, but on bench rest it is great. When you are trying to follow a moving target the 40 is a little tight at distance!
Just my opinion but I shoot distance primarily.