Merwin Hulbert was a major manufacturer of quality revolvers during the 1870's and 1880's. Gun writer and black powder cartridge expert Mike Venturino states that "no revolver ever made exhibits more craftsmanship and precision machine work in its manufacture." During the late 1800's the Merwin company was certainly among the top four large frame revolver makers in the U.S., the others being Colt, S&W, and Remington. Most casual observers suppose that Colt was the leading manufacturer of large frame cartridge revolvers in the 1800's, and may be aware that Remington and S&W made revolvers then, and few are aware of Merwin. However if you look at factory production, you'll find that S&W actually made more large frame cartridge revolvers than Colt during the 1800's, and, based on the frequency of surviving examples encountered, I often wonder if Merwin didn't produce more than Remington!
The Merwin design is unique and required extremely precise machining and hand fitting. The twist open design allows for selective, simultaneous ejection of empty cases while leaving loaded rounds in the cylinder. To open a Merwin Hulbert, the gun is held in the right hand with fingers of left hand wrapping around top of the barrel,. The left thumb pushes the button on the front bottom of the frame backwards towards the trigger guard. The barrel is then twisted towards the left, (which would be clockwise as viewed from the rear of the gun) and pulled forward. This allows ejection of empties. If disassembly is desired at this point, the button on left side of barrel is pushed in and barrel and cylinder slide forward off of the frame.
One feature unique to Merwin design and evidence of the remarkable machining, which is highly prized by collectors, is "suction." On particularly nice examples of Merwins you will find that when you have gun open and barrel pulled forward, if you release the barrel, the barrel and cylinder will pull backwards towards frame as if spring loaded. No springs are involved; it is simply that the close machining of the parts creates a suction which tends to pull the gun back together.
Merwin Model terminology can be a bit confusing at first. We will try to sort it out here:
"Frontier" Models are large frame square butt Models.
"Pocket Army" Models have a birds head grip which comes to a "skullcrusher" type point on the bottom with a large lanyard ring hole drilled through the point. Many of the Pocket Army Models have shorter 3 ½" barrels, although they were also made with the long 7" barrel, most commonly encountered on Frontier Models. Both Frontier and Pocket Army Models can be found in single action or double action configuration.
The evolution of large frame Merwin revolvers went through 4 distinct phases which are called, First through Fourth Models, by collectors. The First and Second Models were made in single action configuration only, and are quickly identified by an open top (no top strap extending from the rear of barrel to frame) and "scoop flutes" on cylinder. First and Second Models are very similar - quickest way to tell them apart is to notice there are two small screws going into the First Model frame above trigger guard where as only one screw there on Second Model. First Models were made in Frontier configuration only, while Second Models were made in both Pocket Army and Frontier configuration.
The Third Model added a top strap from the rear of barrel to frame above hammer, providing an additional locking point for additional strength. Also the flutes of cylinder were changed from scoop flutes to standard type fluting we're familiar with on most revolvers today. Third Model was the first to be offered in both Single Action and Double Action types and again was offered in both Pocket Army and Frontier style. The Fourth Model is probably the most scarce - it's nearly identical to Third Model, but with a rib added to the barrel, (the barrel is round on all the other three Models.)
The large frame Merwins were offered in three chamberings - 44 Merwin Hulbert, 44-40 (the most common chambering, designated by the marking "Calibre Winchester 1873"), and 44 Russian.
The Merwin collector has to be careful, in that many Spanish copies from the same era are found. Some of these are of good quality while others are lesser guns. An original Merwin will usually have both Merwin Hulbert company markings and Hopkins & Allen (although the Merwin guns were made to a consistently higher standard than the H&A guns.) The foreign copies, while interesting and colorful, were worth less than U.S. made Merwins, and may have the words Merwin Hulbert appearing in their markings.
Merwin also made SA and DA small frame revolvers, in two frame sizes chambered for 32 and 38 cartridges; along with a tip up 22 spur trigger resembling the S&W Model One.