The .38 Long Colt was the direct predecessor of the .38 Special . Same dimensions , except a few thousandths shorter . Can be fired in .38 Special guns , in the same way that .38 Special can be used in .357 .
It is used in those conversion cylinders , because 1851 Colt cylinders are too short for .38 Special , with bullet seated normally. There have been such conversion cylinders made in .38 Special , with the caveat of flush wadcutters only .
There are factory loaded .38 LC , primarily specialty outfits for SASS types
Most people load their own , either trimming .38 Spl cases , or ordering brass from Starline .