This is lot #1635 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!
In April 1940, WaPrüf 2 directed Mauser to begin development of a shortened Master carbine with a 490mm (19.3”) barrel, presumably for specialty troops. Development meandered on until July 1942, by which time just 28 rifles had been made, in two series. The first batch were numbered 3-15 and the second batch in the 70s and 80s with a V (“Versucht”, experimental) prefix. Only one other example is known in the US, number V81 in the Aberdeen Proving Ground collection. The development program was dropped in 1942, probably because the need for the rifles had been adequately filled by Brno-production G33/40 carbines instead.