Howdy
One of the functions of the carrier of a lever gun with a tubular magazine is to only allow one cartridge onto the carrier at a time. But the carrier also has to prevent the next round in line in the magazine from entering the carrier.
Very generally speaking, there are two types of mechanisms that work lever guns. Besides the mechanical differences of the Toggle Link actions (the 1860 Henry, 1866 Winchester, and 1873 Winchester) and the later guns such as the Winchester Model 1892, Winchester Model 1894, and the Marlin Model 1894, to name a few, the two types of mechanisms had carriers that functioned differently.
The Toggle Link guns had a carrier that moved straight up to bring cartridges from the level of the magazine to the level of the chamber. Cycling the lever would then return down to allow the next round out of the magazine to enter.
This is a view down into the carrier of an Uberti replica of the 1860 Henry. The carrier is a large brass block that rides up and down in an open area of the frame. The carrier has a large groove milled through the top where a cartridge rides. This rifle is chambered for 44-40. The carrier is in the lower position, in line with the magazine. If you look carefully, the round on the carrier is resting against a vertical wall in the frame. The next round in line in the magazine is being pushed back by the magazine spring against the bullet of the round on the carrier. You can see it's rim pressing against the bullet. In effect, the round on the carrier functions as a cartridge stop, preventing the next round from squirting out onto the carrier. If the round on the carrier is too short, it will allow too much of the round in the magazine to protrude into the space where the carrier rides, and the carrier will jam as it tries to rise past the protruding rim. The carrier is a tall block of brass, and when it rises the front of the block, below the cartridge, then blocks the round in the magazine from emerging. There is a bevel on the underside of the carrier that will allow for some variation in cartridge lengths. If the round on the carrier is a little bit short, the bevel on the carrier will shove a protruding round back into the magazine, allowing the carrier to continue back up. Toggle Link rifles of modern manufacture have a long enough bevel to allow a rifle chambered for 357 Magnum to function with most 38 Special ammunition. However if the 38 Special rounds are too short, the carrier will jam.
This is a view into the carrier area of a Winchester Model 1892. The carrier is in the lower position. It is laying flat, ready to receive a round from the magazine. There are no rounds in the magazine, the follower is visible below the chamber.
In this view, a 44-40 round is on the carrier. The the carrier is tilted up, and the bolt is ready to push the round forward into the chamber.
A slightly different view of the round. As the lever is cycled, the bolt is beginning to shove the round into the chamber.
In this case, the principal is pretty much the same, except there is a bump on the carrier that functions as a cartridge stop. The bump prevents the round from being pushed too far back onto the carrier, so that another round will not exit the magazine, jamming the action.
In each of these cases, cartridge length is critical. Too short a round, and the mechanism will not feed properly. Of course, in the 19th Century, rifles were never chambered for 45 Colt or 357 Magnum. Pretty much only the original Winchester Center Fire cartridges such as 44-40, 38-40, 32-20, and 25-20. There were no shorter variations of any of these cartridges, so the guns were designed to function properly with ammo restricted to a pretty narrow band of acceptable lengths. Modern lever guns have had their mechanisms 'tuned' slightly so that 357 Magnum, which is about 1/10" longer than 38 Special, will feed reliably with both rounds. There is still a limit as to what the minimum length of any cartridge can be to allow it to feed properly in a lever gun.
I suppose with a tilting carrier, a good gunsmith could add some weld to the carrier so that shorter rounds would feed reliably. But then the gun would no longer feed rounds of a longer length reliably.
The Winchester Model 1906 pump 22 gallery rifles got around this by having a little toggle built into the carrier. The toggle would flip down when feeding 22 Long Rifle rounds, but would flip up when 22 Shorts were fed onto it. This allowed these guns to have greater flexibility in feeding ammunition of widely varying lengths.
The Smith Shop has come up with a replacement carrier for modern 1860 Henry, 1866, and 1873 rifles that will allow them to function with short ammunition such as the 45 Cowboy Special. The carrier has a spring loaded cartridge stop on it that allows it to be used with short ammunition such as 45 Cowboy Special in a 45 Colt rifle, or 44 Russian in a 44 Special rifle. This carrier replaces the standard carrier. When it is installed, the rifle can no longer function with the longer ammunition it was designed for. The original carrier can always be reinstalled, but you can't have your cake and eat it too. There is a small amount of gunsmithing required to install the modified carrier into the rifle.
Here is a link to the Smith Shop's replacement carrier.
http://www.thesmithshop.com/cbs45.html
As far as I know, other than altering the original carrier on a tilting carrier rifle such as the Model 1892, there are no replacement carriers for shorter rounds available.
No demand.
In Cowboy Action Shooting, most stages today are written with a maximum of ten rifle rounds to be shot from the rifle. This is because many of the carbines can only hold a maximum of ten rounds. I can recall stages where we shot twelve rounds from our rifles, and those of us with 24" barrels could load them up, but it was not fair to the guys with 20" barrels, they had to reload. Once short rifles with 20" barrels became the preferred rifles for the top shooters, rifle round counts of more than ten pretty much went away.
The original Henry rifle was chambered for the 44 Henry Rimfire round, which was a much shorter round, about the same length as a 45 Cowboy Special. Because the 44 Henry round is no longer commercially available, and because it was a rimfire round, modern reproduction Henry rifles are no longer chambered for that round, but only for the longer 45 Colt or 44-40 round. But there are a few Henry owners who install the Smith Shop carriers into their rifles so they can shoot 44 Russian rounds. Then they can 'load up on Sunday and shoot all week long'.
This photo illustrates the different lengths of some old cartridges. Left to right they are 44-40, 44 Henry Rimfire, 44 S&W American, 44 Russian, 44 Colt, 44 Special, and 45 Colt.
