Here's some info on the round, its been around a LONG time.
http://findarticles.com/p/articles/mi_m0BQY/is_9_46/ai_64259196 Another cartridge in this category first appeared in 1920 and has quietly "been around" ever since --the .45 Auto Rim. What is that, you say? Isn't that a contradiction in terms: auto rim?
Yep, you're right. Technically, cartridges intended for use in self-loaders normally have no rim, headspacing instead on their case mouth. Conversely, cartridges designed for revolvers have rims, right? Yes again, but in this instance with an interesting story behind it.
Ahead Of Its Time
The story of the .45 Auto Rim is also the story of a famous gun, because it was designed in 1920 by Remington-Peters to be used in Smith & Wesson's about-to-be-introduced ".45 Hand Ejector U.S. Service Model Of 1917." Unveiled by S&W's president. Joseph Wesson, on September 16, 1917, the M1917 is important to firearm history.
Even though the M1917 was a revolver, it was intended from the outset to utilize the .45 ACP cartridge. This was accomplished via an ingenious device that held three cartridges together and provided head spacing as well -- the now-famous "half-moon" clip.
I only have one "string" to the deal.... You MUST post a pic of the pistol that shoots this round.
![Grin ;D](https://www.michaelbane.tv/forum/Smileys/default/grin.gif)