This is lot #3213 in the upcoming RIA Premier Auction. It was scheduled for April, but has been postponed – check their web site for upcoming Online Only auctions every month, though!
Patented in 1884 and designed by retired Civil War General William Franklin, this was an effort by Colt to win a military contract for a repeating rifle. It was a wholly new rifle (not a conversion) that operated like a Gras action, was chambered for .45-70 cartridges, and fed from a 9-round hopper type magazine. Only 50 were made, and they underwent extensive trials with both the US Army and Navy in 1887 and 1888. Despite successfully firing some 4,000 rounds, none were ordered – probably because the magazine would have been far too easily damaged in field use.