These are Cimarron/Uberti 1872 Open Top .44 Colt cartridge revolvers.
I have owned them for four or five years and use them on those occasions I get to shoot Cowboy Action events.
No major issues, I have broke hand springs and a loading gate spring, I would recommend spares of these be kept on hand along with a hammer spring.
These springs are the parts that will give you the most probable source of a breakdown.
To clarify the caliber because this can become confusing to some folks,
Modern .44 Colt is nothing more than a shortened .44 special case with a slightly thinner rim.
This cartridge uses the same .429" diameter bullets as the special and weights of 180 to 240 grains can be used though the powder charges are only safe at about 20% less than a standard .44 special load.
Try anything heavier in a smokeless powder load and the non reinforced frame revolvers will quickly loosen up and get out of time.
.44 Russian cartridges may also be loaded and fired in these revolvers too, I shoot them probably more than the .44 Colt cartridges since .44 Russian cases are cheaper than .44 Colt where I get my stuff.
Original .44 Colt loads were heel loaded ,(like a .22 long rifle cartridge), .454" diameter, and a real pain to load or keep on target.
Sometimes the bullets fell out of the cases and tied up the revolvers too, a real pain and no more needs be said about it.
Real blackpowder loads do not do well in these revolvers either.
No matter what type of lube technique I have tried the guns very quickly foul out to the point the cylinder will not rotate.
Clean Shot and Clear Shot blackpowder substitutes work fairly well but accuracy is no where near as good as smokeless loads in my revolvers.
If you appreciate very early cartridge firearms designs one of these revolvers is well worth owning.