This is lot #462 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!
The 1970s were a period with epidemic levels of airline hijackings, and this revolver was designed by Colt at the request of Eastern Airlines to arm pilots. To address concerns about over-penetration of aircraft skin or windows (or of a potential target), a projectile made form plaster of Paris was designed. Colt started with MkIII and MkV Lawman snub-nosed revolvers, and replaced the cylinders with a new one made of Zytel, with six steel sleeves installed. Each sleeve held a sealed cartridge, with a plaster bullet inside a sabot (the plaster was brittle enough that engaging rifling would shatter it). The cylinder was disposable, meant to be discarded when empty. Only a small number were made, as Eastern Airlines ultimately decided to use Federal Sky Marshalls instead of arming its pilots, and that was the end of the project for Colt.