March 04, 2020
By Bob Campbell
When America entered World War I, we had perhaps 30,000 1911 semiautos. We needed to arm every soldier for what was shaping up as a pistol war. Colt simply could not fill the need for 1911 handguns and neither could Remington UMC or other contractors.
Smith & Wesson had production capacity geared up and simply rechambered its big-frame 1917 revolver for the .45 ACP cartridge—as did Colt with its New Service. While the Smith & Wesson and Colt are each big burly revolvers, the Smith is slightly smaller and, in my opinion, better balanced.
Since the .45 automatic cartridge does not have a case rim, the rounds simply fell into the cylinder. After early testing, a properly chambering cylinder design was implemented, although the ejector star would not eject a rimless cartridge.
Smith & Wesson developed the half-moon clip that held three cartridges, and it was actually Daniel B. Wesson’s son, Joseph, who invented the moon clip. While developed by Smith & Wesson, the Army requested that Colt be allowed to use the moon-clip design as well.
Those clips neatly solved the problem of using a self-loader’s cartridge in the revolver by providing headspace with the .050-inch-thick clips. The cartridges were issued in half-moon clips.
The design resulted in the fastest revolver to load and unload ever made in America. With a conventional revolver, the barrel must be pointed upward to quickly unload the cylinder. Not so with the 1917. Simply hit the ejector rod, and the half-moon clips and cartridges are ejected—a neat trick, no matter the angle. Then slap loaded moon clips in and you are ready to go.
While the original set of two moon clips were faster than any conventional revolver, the modern six-shot moon clip is even faster. I fired my 1917 revolver with moon clips and without. As long as you keep load pressure within standard .45 ACP limits of 18,000 to 21,000 psi, the revolver performs well. The 5.5-inch barrel N-frame revolver is faster handling than the heavy-barrel magnums with target sights and clears leather quickly.
But there’s another side to this story. After World War I, the U.S. military declared the 1917 revolvers as surplus. Cops, outdoorsmen and anyone who wanted a high-quality big-bore revolver latched onto them because they were available for a much lower price than the .44 Special or the .38-44 Outdoorsman.
The .45 Auto Rim (c.) features a heavy rim that allowed it to work in 1917 revolvers. It can be loaded to levels similar to the .45 Colt (l.) and .45 ACP (r.). Most shooters did not want to use the moon clips the 1917 made famous. While great for combat, they were an aggravation for day-to-day use. Then Remington introduced the .45 Auto Rim cartridge, which is simply a .45 ACP with a revolver-like rim. The cartridge headspaces properly and is ejected by the ejector star. This gives you the advantage of using the moon-clipped revolver for personal defense or competition and the .45 Auto Rim for hunting and target practice.
The 230-grain lead bullet in the original .45 Auto Rim loading is loaded to .45 ACP velocity, about 830 fps. Handloaders realized that the case capacity and strong head of the .45 Auto Rim allowed improving on .45 ACP ballistics, and the .45 Auto Rim easily reaches the performance of standard .45 Colt factory loads in a quality double-action revolver. It is not difficult to jolt a 255-grain semi-wadcutter to 900 fps. A 225-grain flatpoint may be sent to 1,000 fps.
Take care in using those handloads because the condition of original handguns varies considerably, but each load is within the realm of .45 Auto Rim performance.
One of my present .45 ACP revolvers is an original Brazilian-contract M1937. It has been used a good deal and is not a collector’s item. The old-style, long, double-action trigger is smooth, it is as rugged as any handgun, and it is accurate enough for most chores.
I enjoy loading for this revolver, and it will accept any load I have worked up for the 1911 .45. I normally run a 200-grain semi-wadcutter at about 800 fps, a mild and accurate load. Buffalo Bore offers factory loads in .45 Auto Rim that are a godsend to those who do not reload. My choice is the 255-grain 820 fps load.
While many carry magnum revolvers when hiking or traveling, I find the .45 ACP/.45 Auto Rim combinations suit my needs better.
