Howdy
After wanting an Uberti replica of the 1875 Remington cartridge revolver for a long time, I was able to find an affordable actual antique 44-40 Remington 1875 a few years ago. (Problems buying the replica here in MASS, I won't go into the details here)
Interestingly enough, the originals were never chambered for 45 Colt. 44-40 and a proprietary 44 Remington cartridge with a heeled bullet, but other than perhaps 1/2 dozen chambered for 45 Colt for the Army Trials, the 1875 model was never sold to the general public chambered for 45 Colt.
Unlike the replicas, there was no spring loaded cylinder latch mounted just in front of the cylinder. The very long cylinder pin had a spring loaded catch all the way at the front. Depressing this catch allowed the cylinder pin to be pulled forward enough to remove the cylinder.
Although very similar in design and operation, the 1875 Remington never caught up in sales to the Colt Single Acton Army. The SAA had contracts with the Army starting in 1873, and by the time Remington offered up the 1875 model, Colt had too strong a foothold with military contracts. Also, unlike the Colt, the extractor of the Remington was exposed to the elements, which was a strike against the Remington design.
The video is correct about the grip shape of the 1875 Remington being different than the grip shape of a Colt. The grip of the Remington extends further back from the trigger guard than the Colt.
Notice how much further back the grip of the 1875 model extends than the grip of this replica 1858 Cap & Ball model. A lot has been written about the web under the barrel of the 1875 Remington. Lots of stuff about how much stronger it made the revolver. Frankly, I don't buy it. The web is attached to the barrel by one screw up at the front, and a slip fit over a pin at the frame. Not a recipe for a strengthened barrel to frame connection. Personally, I have always felt that the web under the barrel of the 1875 model was simply a stylistic attempt to keep the familiar shape of the loading lever of the 1858 Cap & Ball revolver.
The later 1890 Remington reshaped the web under the barrel, almost eliminating it.
The pin securing the rear of the web to the frame can be seen in this photo of my Model 1890 Remington. The same arrangement as the 1875 Model, but the web was cut back enough to reveal the pin.