For the Mexican shooters, the big plus of the .38-44 guns are that the cylinders will not accept the .357 Magnum cartridge and allow to let the cylinder close. The chamber-step prevents this. Sometimes the cylinders are drilled-out to accept .357 rounds and those are no good to us because the Army sometimes checks. We keep some .38-44 cylinders at the Custom Shop in both blue and nickle so that N-frame guns remarked to .38 Special can be registered. Then we take the cylinders back because the guns are never going to be checked again, generally. Also, 8-shot 627's are registered with 6-shot nickle Heavy Duty cylinders affixed. The 8-shot guns would not be safe to shoot with a 6-shot cylinder because the barrel to cylinder axis is slightly off, but it works for registration. I think that over a 5-year period every Heavy Duty cylinder that was advertised on Gunbroker ended up in Mexico. Yes, that was us.
Another S&W revolver that took the .38-44 cartridge was the Outdoorsman, later numbered as the Model 23. Several members have those and they are beauties. Numrich had unfinished Outdoorsman barrels for 20.00 bucks for years, but I think almost all those went to Mexico as well. I still have 3 in my parts kit down in our San Miguel loading room. They are unfinished but otherwise ready to mount and marked as ".38 S&W Special Ctg.".
In this photo (taken in one of a Equipal Chairs that now sits at my Mother-in-Law's awaiting our return) sits my friend Harold's Transitional Outdoorsman -- made about 1948 -- with a refinished Numrich barrel installed as the original was bulged when we got it. Harold is one of the World's richest men and fitted out his Outdoorsman with Cokes we bought directly from Lee Jarrett, owner of the S&W Forum website and whom I have met and corresponded with. Below it is my Model 28 remarked as a Model 23, and Phil Roettinger's Non-Reg. Magnum and finally my Heavy Duty. The Outdoorsman normally sports a 6.5 inch barrel, with a pinned from sight ramp and sight allowing the installation of other front sights as the owner chooses. The Outdoorsman is like a Model 27 but with K-38 style barrel and frame top-grooves instead of checkering. And it will withstand the same Elmer Keith loads, and is chambered for the .38 Special case.
A nickle plated 4-inch Heavy Duty. I doubt the nickle is factory original, but it shoots fine. This belongs to a friend of mine in Guadalajara, but I had it for a while to fix some action troubles he had with it.