I like 40-44mm over a 50mm, so that it allows the scope to sit lower on the rifle and the shooter can get a better cheek weld. The only advantage to a 50mm objective is a wider field of view at any distance. Contrary to popular belief, it doesn't allow any more light to enter the scope. Thats what all of the coatings on the lenses are for. For a really nice, affordable scope, I would look at the Nikon Buckmaster II 4-12x40. Then start looking at the Vortex line up as they make some great glass, with one of the best warranties around. Of course, you can't beat a Leupold for quality and clarity. I watched a video the other day on the Burris Predator Quest scope and it looked like a great scope and had a reticle designed to long range coyotes and varmints. I haven't looked through the Burris yet, but if I was in the market, I would have to find one and check it out. I haven't scoped a new rifle in quite a while but, the next time I do, I plan on using DNZ scope mounts. They are as solid as it comes and tend to put the scope reticles almost where they need to be. You still need to bore sight, but it isn't off by to much with the DNZ brand.
I have been using a Nikon Prostaff 4-12x40 on my Savage .204 Ruger and find myself rarely taking it off of 4 power when I shoot something. I keep it on low power in case a coyote or bobcat pops out close and plan on zooming if they are at distance, but I end up just putting the crosshair on them and squeezing the trigger. I forget to increase magnification in the excitement. It has worked so far, but one day it may bite me in the arse.
