Home Forums Hunting & Shooting Hunting Optics Best scope for a slug shotgun?

I just bought an older Redfield 1x4---20mm from the classifieds here. It was made in Denver. I plan on putting it on my Remington 870. It's a smooth bore--imp cly. I'm good out to 75 yards maybe a bit farther. Where I hunt in Ohio----75 yards is a long shot.