My daughter and I were sitting side by side in a stand one evening a couple of weeks ago. I was holding an old Marlin 336 30-30 with a nice clear Leupold M8 3x duplex. She was holding a Howa Mini 6.5 Grendel topped with an older Nikon Buckmasters 3-9x40 duplex. Her scope was good for 12-15 minutes after my old straight tube Leupold bowed out and that older Nikon is far from cutting edge glass.
Set to the same magnification?