A few years ago for my 1917 and .45 1950 Target I became fed up with using 45 ACP in moon clips and 45 AR brass just wasn't that available and too pricey when found. Since I reload, the price advantage of ACP ammo is irrelevant to me.
As a Cowboy action shooter I was aware of a new cartridge called the Cowboy 45 Special which has the case length of 45 ACP (.895").
I reloaded and used them in my Single Action Colts and Rugers very successfully for efficient light competitive loads. See them here:
cowboy45brass
They shot even better in my 45 ACP DA revolvers when taper crimped because there was no bullet jump to the chamber throat like in the 45 Colt SA cylinders. The case mouth headspaces on the square chamber shoulders in ACP cylinders and the case heads protrude from the chambers exactly the amount as 45 ACP cases.
I've also shortened Starline 45 S&W Schofield solid head cases to .895 and they work just as well. I no longer need moon clips and of course with the rim, they ejected perfectly in DAs. I reload them with ACP dies and a 45 Colt shellholder with my standard ACP loadings. They give excellent accuracy in my Smith DAs. And my Smiths are correctly marked since S&W has always rollmarked their ACP guns just ".45 Caliber".
I suppose one could call them modern 45 S&W Specials. Now I just need to find a 1st run 455 Triple lock with a cylinder already modified to shoot 45 ACP or a spare ACP cylinder to fit to it, to have a replica 45 S&W Special Triple Lock that I can shoot w/o depreciating the value of a highly collectible original. Hmmmmmm...how about a 45 Spl TL Target? I have a refinished triple lock 44 target and a TL 455 barrel. Anyone have an orphan pre war HD or 44 Spl cylinder to rechamber?
And properly shortend and sized 45 Schofield cases could easily be used to make 45 Special ammo for an original 45 Spl Triple Lock if one wished to shoot it.