I have a Simmons .44 mag scope mounted on a 300 Winchester Mag that I bought about 20 years ago, and is still dead on. So never really know. I tend to like the Nikon Prostaff scopes, my eyes arent good enough to tell the difference in the glass between those and a Leupold, and have had no issues with holding zero on my .308 or .223. Granted, not a ton of recoil with those.