I would give $750 for that Mountain Gun, no doubt about it. Its possible that someone might be willing to pay $800 - $850. New, unfired in box definitely adds a premium. The .45 Colt is a caliber which some shooters (me included) really covet ( specially those who reload). Are you selling or buying ? If buying, you won't be disappointed, if selling, you'll always regret letting this one get away.