I had a Vortex Diamondback 2-7 on my H&R Ultra Slug 20 ga. and it worked fine, but I replaced it with a Nikon 2-7 slug scope to put that Vortex on something else. Only issue I have with the Nikon is the crosshairs are a bit to thick for me. I prefer the thinner crosshairs that the Diamondback has.