To provide a bit more info on Mr. Chaney's question about the Remington 51: it's a golden oldie designed by John Pedersen who brought you the Remington .22 pumps, the Remington 14 centerfire pump rifles, the Pedersen device for the 03 Springfield of World War I fame, the Remington Model 10 pump shotgun, etc. I forget when the 51 was discontinued: prior to 1930 I'm sure. Pedersen was a very active and successful designer and if I recall right, the US Navy was considering during World War I possibly adopting one of his designs in lieu of the Model 1911 Colt. Mostly because M1911 production was so backlogged. Remington was sort of late getting into the pocket pistol market which was actually strongest prior to the US entry into World War I and they never sold as many as Savage or Colt (the biggest player in the field using Browning's patents). But many more than the Smith and Wesson .35s or even rarer .32s which were a design licensed from the Belgian Clements company.
Another uncommon thing about the Remington 51 was that unlike the Colts or Savages, there were more .380 Remington .380s made than .32s.
Never have seen all that many of them. Neat guns. I'd imagine getting parts for them could be problematic should anything ever break.