The "45 Long Colt" title came from the cavalry days, and was used to help soldiers understand the differences between the 45 S&W Schofield (short) loading, and the 45 (long) Colt loading. You could fire the Schofield load in the S&W Schofields, or the Colt SAA, but you couldn't shoot the Colt loading in Schofields. Since both revolvers were in use during the same period, often times Schofield ammunition was issued to troops because you could use it in either revolver. "Long" is also a commonly used term for Colt ammunition during that era, witness the 38 Long & Short Colt, and the 41 Long & Short Colt. 45 "Long" Colt may not be technically accurate, since Colt certainly didn't officially name their cartridge thusly, but it certainly served a real purpose.