PS There's a reason for it being called Long Colt, even though that's not technically its designation. It goes back to a period when the US Army had adopted two main revolvers, the S&W Schofield (chambered in .45 Schofield) and the Colt SAA (chambered in .45 Colt).
The problem was that the .45 Schofield was identical to the .45 Colt, other than case length (it was a bit shorter), so they were one-way-compatible only. Thus logistical problems arose when orders for more ammo were delivered to headquarters. If they asked for .45 Schofield and received .45 Colt, they'd be out of luck, because they wouldn't chamber in the Schofield revolver, so the habit developed of referring to .45 Colt as .45 Long Colt, in order to address the confusion.
Eventually the problem was solved by only ordering .45 Schofield ammo, which would operate in both revolvers, but the tradition of referring to .45 Colt as Long Colt had already been established, and the folks who had been in the military during that confusing period continued to use that terminology upon rejoining civilian life, so by that means it came to be established in common practice.
