Those who shoot data for various reloading manuals have established two levels of chamber pressures for the .45 Colt in modern revolvers of current production. Level One data is recommended for the Colt Single Action Army built to handle smokeless powder and top-quality reproductions of same. Maximum velocity with a 250-grain bullet is in the neighborhood of 800 to 850 fps, which closely duplicates the performance of original .45 Colt loads.
The popular Brownells/Taylor .45 Colt conversion made for the Ruger Old Army cap-and-ball revolver also belongs in this group, but since its short cylinder reduces overall cartridge length to less than for the Colt, maximum powder charge weight should be kept a bit below the published maximums. Jacketed bullets can be used, but I prefer cast or swaged lead bullets when loading to Level One velocities.
Level Two loads are appropriate for the Freedom Arms Model 83 and Ruger New Model Blackhawk revolvers, the latter built on the .44 Magnum frame. Ruger has built Blackhawks in .45 Colt on the .357 Magnum frame for one of its distributors, and those should be treated as Level One revolvers. Maximum velocity with a 250-grain bullet for Level Two loads is 1,200 to 1,400 fps, and this makes the .45 Colt equal in power to the .44 Magnum at lower chamber pressures (due to the .45’s greater case capacity and larger bullet diameter).
The .45 Colt is one of our all-time great cartridges, but handloading it to its full accuracy potential can be challenging. The case has much more capacity than needed for Level One smokeless-powder charges, and that can cause shot-to-shot velocities to vary considerably, although it does not always affect accuracy enough to notice. There is also the danger of double-charging, but that is easily avoided by visually checking each case after all have been charged.
Most Meaningful Match-Up
The challenges of coming up with an accurate .45 Colt load are not restricted to the cartridge. The groove diameters of most revolver barrels range from .450 to .452 inch and jacketed bullets run from .451 to .452 inch, so we have good match-ups there. But for best lead-bullet accuracy, the important match is bullet diameter to chamber throat diameter. If throat diameter is smaller than groove diameter, as is the case for some Ruger Blackhawks, acceptable accuracy with either jacketed or lead bullets may not come unless the throats are reamed out to approximately .452 inch with the #513-000-001AE .45 Cal. Revolver Throat Reamer from Brownells. It is a modification most shooters can handle.
The cylinders of some revolvers have chamber throats quite a bit larger than barrel groove diameter, which is the case with Colts built after World War II. With the exception of its handsome custom grips made by friend, my 1970-vintage New Frontier is factory original. It has throat/groove diameters of .4570/.4525 inch, while the 2012 New Frontier I shot for this report measures .4572/.4502 inch. Some revolvers with oversized throats shoot lead bullets of the proper diameter more accurately than jacketed bullets, and my New Frontier is a good example. Other revolvers with oversized throats may deliver acceptable accuracy with both types of bullets, and the current-production New Frontier proved just that.
Best accuracy with lead bullets usually comes with those measuring the same as or slightly larger than throat diameter, which for my Colt means the RCBS #45-270-SAA. When cast of wheel weight metal in my particular mold, it measures .4575 inch and weighs 280.0 grains. Some guns with oversized throats will shoot slightly smaller bullets quite accurately. Examples are the .455-inch Hornady 255-grain Cowboy, along with the Lyman #454190 and RCBS #45-255-SWC, both dropping from my molds at .454 inch. All proved to be quite accurate in the 2012 New Frontier. As factory loads go, the Remington 255-grain SWC and Hornady 255-grain RN, both loaded with .454-inch lead bullets, are often the most accurate.
Virgin cases require full-length resizing prior to loading in order to reduce interior diameter for adequate tension on bullets. If this is not done, the crimp alone may not be sufficient to prevent recoil from causing bullets to creep forward enough to interfere with cylinder rotation. Most full-length resizing dies reduce interior case diameter to around .445 inch, which is okay for bullets measuring .451 to .452 inch, but when an expander die is then used to increase case diameter for bullets measuring .454 inch and larger, the brass is worked excessively, often resulting in reduced case life. A dual-ring carbide resizing die from Redding is the answer.
A carbide ring at the mouth of the Redding die reduces case diameter enough for an easy fit in the chamber, while a slightly smaller carbide ring located deeper in the body of the die reduces the front section of the case a bit more for adequate tension on the bullet. Using that die along with an expander die with a button of the correct diameter for the bullet being loaded is the way to go when loading for revolvers with oversized chamber throats. The most commonly recommended expander plug diameters are .001 Inch smaller than the cast bullet being loaded and .002 inch smaller than the jacketed bullet. Those work for Level One loads, but when loading jacketed bullets for heavier-recoiling Level Two loads, I use an expander .003 to .004 inch smaller than bullet diameter. Expanders of various diameters are available from RCBS.
Even when held in place by a heavy crimp, a bullet can creep forward a bit during recoil, and if it protrudes from the mouth of the chamber, it will tie up cylinder rotation. I prefer to maintain a maximum overall cartridge length that positions the nose of a bullet no closer than .010 inch from the front of the cylinder. Due to differences in cylinder lengths, maximum cartridge length will vary considerably, and for the four guns featured in this report, they are 1.770 inches for the Freedom Arms Model 83, 1.735 inches for the Ruger Blackhawk, 1.645 inches for the Colt, and 1.585 inches for the Ruger Old Army with its Brownells/Taylor conversion installed.
Some lead bullets -such as Hornady’s 255-grain Cowboy and 230-grain RN- don’t have crimp grooves and when used in Level One loads, taper-crimping with a .45 ACP die will hold them in place. The same applies when the maximum overall cartridge length allowed by a particular gun positions the mouth of a case beyond the crimp groove and on the forward driving band of cast bullets, such as the RCBS #45-270-SAA and Lyman #452454. If the mouth of the case is a bit beyond the front edge of the driving band, a regular roll crimp should be used. This also applies to the Hornady 200-grain lead semiwadcutter that is intended for the .45 ACP but often delivers excellent accuracy from the .45 Colt. Due to the heavier recoil of Level Two loads, the mouth of a case must be heavily roll-crimped into the cannelure of a jacketed bullet.
Pointers on Powders
About 30 different powders are listed in handloading manuals for Level One .45 Colt loads, and I have included most of them (scroll to bottom of article to see attachments). Unique is the old classic for this cartridge, and I’d say it is still the most popular among those who are seriously into loading this cartridge. If I could have only one powder for Level One loads, it would be Unique. It and AA No.5, SR 4756, Universal, and SR 7625 were excellent accuracy performers in the test guns, although others may deliver the same goods in other revolvers.
Powders best suited for Level Two loads include W296, H110, Lil’Gun, 2400, H4227, IMR-4227, and AA No. 9, with 2400 producing the brightest muzzle flash. Compared to Level One powders, all have extremely slow burn rates, so starting charges should not be reduced below those shown in various reloading manuals.
Team up a quality bullet with the right powder and five-shot accuracy at 25 yards for a good revolver in .45 Colt should be no worse than 2 inches. If the gun is a good one and its shooter is having a fine day, 1-inch and smaller groups come often enough to rule out luck.