Sixguns And The .45 ACP

Loading For Auxiliary Cylindered
Single-Action Revolvers

By John Taffin

Forty-five years ago, graduate school took me 500 miles away from my family. One of the few pleasant distractions I had at the time was to visit the little gun shop on the main street of town.

One particular day as I wandered in I spotted something in the display case which looked out of place. It was a large-framed Ruger Blackhawk with a 7-1/2-inch barrel. However, it was not a .44 Magnum, but the first example I had ever seen of a .45 Colt Blackhawk. Of course I purchased it. It didn’t take long to learn what the .45 Colt was capable of in the strong Blackhawk.

I was soon shooting 300-grain bullets at 1,200 fps. My Ruger .45 Colt performed so well it would be several years before I paid attention to the little red bag in the box. This particular sixgun was a Convertible Blackhawk, that is, it was not only a .45 Colt it also had an auxiliary cylinder in .45 ACP. I know at the time I figured this is something I would never need, nor even want to use. Why would anyone want to shoot the .45 ACP when they had such a great .45 Colt sixgun?

At the time I had a military surplus 1911 and a pretty good supply of military hardball ammunition. One day, in what must’ve been a weak moment, I switched cylinders in the Blackhawk, tacked up the lid of a mayonnaise jar at 25 yards, and proceeded to shoot the military hardball through the Blackhawk while in the back of my mind I was thinking this will prove how worthless having this extra cylinder will be. It didn’t happen! Those first six rounds fired offhand out of that Old Model .45 Blackhawk all centered themselves in the lid of the mayonnaise jar.

That day I learned how valuable an extra cylinder, especially chambered in a semi-automatic cartridge, could be. When Freedom Arms began offering their .454 Casull, which eventually became known as the Model 83, with an extra cylinder in .45 Colt, I returned mine to the factory to add two “semi-auto-caliber” cylinders in .45 ACP and .45 Winchester Magnum. In the late 1990’s Freedom Arms introduced their mid-frame single action, now known as the Model 97, in .45 Colt with an extra cylinder chambered in .45 ACP. By now, I had learned not to hesitate and realized how valuable extra cylinders were.

There is nothing new or unusual about sixguns being chambered in semi-automatic cartridges. In fact, 100-years ago we entered WWI and found ourselves short of 1911 Government Models. Both Smith & Wesson and Colt converted their large-framed sixguns to the M1917 .45 ACP. Double-action revolvers such as these use half-moon clips for ease of loading and especially unloading. Some work without the clips, while others would seat cartridges too deeply in the cylinder for the firing pin to reliably ignite the primer. This has never been a problem with any of my single-action sixguns and unloading is accomplished with the ejector rod the same as with a rimmed cartridge.


Targets fired with .45 ACP sixgun loads in the Ruger Blackhawk are powerful,
accurate, and pleasant shooting. Cylinders chambered for the .45 ACP are
normally cut with case mouths of 0.451 or 0.452 inch (above).


I have had experience with six single-action sixguns with auxiliary cylinders chambered for the .45 ACP. Four of these are Rugers, including a trio of the relatively new Flat-Top Convertibles, two are from Freedom Arms, and one from the now-gone USFA. Generally speaking, these cylinders are cut with tighter chambers than .45 ACP semi-autos. Cartridges which routinely feed and chamber correctly in many (actually most) .45 ACP semi-autos will not chamber in the revolver cylinders.

For decades when loading for the .45 ACP semi-auto using any bullets which have a shoulder I preferred to have just a small part of the shoulder showing above the case mouth. In most .45 ACP semi-autos this seems to work just fine. However, loading the same style bullets in .45 ACP cases for use in sixgun chambers results in a cartridge which does not enter the chamber far enough to allow the cylinder to rotate. This is especially true with 200-grain SWC bullets designed for the .45 semi-automatic and especially so for both Keith and Keith-style bullets.

Elmer Keith designed two .45 bullets for sixguns. One is No. 454424 for the .45 Colt which drops out of my mold at just under 258 grains while the other is 452423 specifically for the .45 Auto Rim and these weigh just under 240 grains. Both are semi-wadcutters with large flat noses, or meplates. They must be loaded in .45 ACP cartridge cases either having the front of the shoulder flush with the end of the mouth of the case (or slightly below) or they will not chamber.

Anytime I am working with a new sixgun or semi-auto, I load a few dummy rounds with whatever bullet, case and dies I am using to make sure they will chamber. This is especially important when loading .45 ACP cartridges for use in sixguns. It is a lot easier, and a lot less expensive to start with a few dummy rounds rather than winding up with several hundred rounds which will not chamber. Surprisingly, the chambers on the .45 ACP cylinder of my original Blackhawk from more than 45 years ago are actually tighter than the chambers of either the Freedom Arms Model 83 or Model 97.

Since we already have these sixguns chambered in .45 Colt, which is one of the all-time great sixgun cartridges, why should we mess with extra cylinders in the .45 ACP? Actually, there are several reasons, not the least of which is .45 ACP brass not only seems to be much easier to find, it is also much cheaper than .45 Colt brass. Then there is the fact less powder is needed to duplicate .45 Colt ballistics in the .45 ACP case. For example, with Alliant’s Unique powder, 6.0 grains in the .45 ACP case under the 258-grain Lyman Keith 454424 accomplishes what it takes 9.0 grains to do in the longer .45 Colt case.

Of course, this is meaningless unless we get comparable, or even better accuracy from the shorter case. It would be natural to believe the shorter the case the less accuracy because of the distance the bullet travels from the short case in the long cylinder. This does not seem to be the case. Using the 454424 Keith bullet over 6.0 grains of Unique in .45 ACP cases gives muzzle velocities of 976 fps in the 7-1/2-inch Ruger Blackhawk, 968 fps in the 4-3/4-inch Freedom Arms Model 83, and 955 fps in the 5-1/2-inch Freedom Arms Model 97. Group size for 5 shots in the Blackhawk measures 1-1/2 inches at 20 yards while the two Freedom Arms group sizes for 4 shots are 3/4 and 5/8 inch respectively.


Targets fired with .45 ACP sixgun loads in the Freedom Arms Model 83 showcase its versatility.


The Freedom Arms Model 83 .454 Casull is exceptionally versatile with the
auxiliary cylinders in .45 Colt, .45 ACP, and .45 Winchester Magnum.

The reason for the difference in number of shots is the fact the Ruger has a 6-shot cylinder while the other two from Freedom Arms both have 5-shot cylinders. (With revolvers I almost always measure groups with one shot less than the total capacity.)

The bullet I use most in .45 ACP loads for use in semi-autos is the 200-grain SWC which is epitomized by the Hensley & Gibbs 68, the RCBS 45-201, and most assuredly the Oregon Trail 200 SWC. There was a time when I felt I had to cast my own bullets to get the best accuracy, however, the arrival of Oregon Trail several decades back changed my mind. Their bullets often outshoot my very carefully cast, sized, and lubed ones. This bullet over 6.0 grains of Red Dot clocks 1,008 fps in my 7-1/2-inch Blackhawk and yields a 5-shot group of 7/8 inch at 20 yards while the same load registers 966 fps from the shorter 5-1/2-inch Freedom Arms Model 97 sixgun with a group of 1-1/4 inches. The same bullet over 6.0 grains of Green Dot yields muzzle velocities of 1,114 fps and 1,096 fps respectively with groups of 1-1/8 and 1-1/4 inches.

The load I worked up for use in .45 ACP semi-autos with lighter recoil springs is put together with the same bullet over 4.0 grains of Bullseye. This makes a gentle-shooting load in the Freedom Arms Model 83 and Model 97, yielding groups of 1 inch or less with muzzle velocities right around 750 fps.

Finally, for an all-around everyday working load for the Old Model Ruger Blackhawk, the Oregon Trail 250-grain roundnose flatpoint over 8.0 grains of HS6 clocks right at 925 fps, which is quite a bit above standard .45 Colt loads, and puts five shots in 3/4 inch at 20 yards. It would be hard to ask for anything better than this from an old .45 Colt/.45 ACP single action sixgun.


The rounds offering several differing levels of power are (from left to right)
.454 Casull, .45 Colt, .45 ACP and .45 Winchester Magnum.





Alliant Powder
P.O. Box 856
Lewiston, ID 83501
(800) 379-1732

Freedom Arms
P.O. Box 150
Freedom, WY 83120
(307) 883-2469

Hodgdon Powder Co.
6430 Vista Dr.
Shawnee, KS 66218
(913) 362-9455

Lyman Products
475 Smith St.
Middletown, CT 06457
(800) 225-9626

Oregon Trail Bullets
PO Box 529
Baker City, OR 97814
(800) 811-0548

605 Oro Dam Blvd.
Oroville CA 95965
(800) 533-5000

Sturm, Ruger & Co.
200 Ruger Rd
Prescott, AZ 86301
(928) 778-6555

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