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The Ultimate Reloading Manual
Wolfe Publishing Group
  • alliant reloading data
  • reloading brass
  • shotshell reloading
The Ultimate Reloading Manual
load development

Top 10 Reloaded Handgun Cartridges #8: .45 Colt

Author: Staff
Date: Jul 13 2021

The Lipsey’s Ruger New Model Blackhawk .45 Colt is a practical working and field revolver.
©2017 G. Hudson photo

Following the success of a limited production Ruger New Model Blackhawk .44 Special revolver built for Lipsey’s during 2008-09, Ruger recognized its popularity and made it a regular production catalog item. In a subsequent conversation with Lipsey’s Jason Cloessner, we discussed many other firearms that would be suitable for another exclusive, limited production.

The revolver is capable of firing three of the four cartridges, including the
(1) .45 ACP, (3) .45 Schofield and (4) .45 Colt. With a slight headspace
modification, as originally performed on Colt and Smith & Wesson
U.S. Model 1917 revolvers, the .45 ACP cylinder can also fire the
(2) .45 Auto Rim.

I encouraged Jason to consider the same gun, but chambered in .45 Colt, and throw in a spare cylinder chambered for .45 ACP/Auto Rim and in blued or stainless steel. He asked, “Should we make it on the 50th anniversary .44 frame or .357 frame?” I responded, “Both would certainly sell, but there would be far more demand for the .45 Colt built on the smaller .357 flattop frame and would be the first time Ruger has offered such.” Jason took my suggestion, and the revolvers remain available from Lipsey’s dealers (

The New Model Blackhawk .45 is offered in 45⁄8- and 5½-inch barrels in blue or stainless steel. A blued version with 5½-inch barrel and a stainless steel with 45⁄8-inch barrel were ordered. I gave them a good going over finding overall quality, fit and finish. The only disappointment was that the .45 ACP cylinders are intended for that cartridge only. If Ruger would have changed the headspace to the same specifications as originally used on U.S. Model 1917 revolvers from Colt and Smith & Wesson, it would have also housed the .45 Auto Rim cartridge. With that said, it is simple and inexpensive to mill the back of the cylinder to accept that cartridge. I was especially pleased that the “warning and instruction manual” notice was cleverly placed on the bottom of the barrel, making the revolver notably more attractive.

The chambers of both New Model Blackhawk revolvers are cut to
SAAMI minimum dimensions and feature throats measuring around
.452 inch, an ideal combination for accuracy and long case life.

Internal dimensions of both guns were correct. The barrel-cylinder gaps were .004 and .005 inch, respectively. Throats of each of the .45 Colt cylinders measured exactly .452 and were precisely uniform, while both .45 ACP cylinders had similar measurements. This throat size was ideal for general use and top accuracy with jacketed and cast bullets. The chambers also measured on the minimum side of SAAMI dimensions, which aided in cartridge alignment and accuracy, and worked cases less, resulting in longer case life. Having shot Ruger .45 Colt and .45 ACP revolvers manufactured from 1970 until present, to my notion these are the best, most correct chambers the company has ever offered. Incidentally, chamber-to-bore alignment was good. Barrel forcing cones were evenly cut at 11 degrees and the rifling looked excellent.

The Lipsey’s Blackhawk features a fully-adjustable
Micro rear sight housed in the flattop-style frame.

The stocks are an ivory-like plastic with the Ruger medallion and considering the quality and usefulness of these sixguns, I’ve a notion to dress them up with bighorn sheep, stag or fancy walnut stocks.

The front sight was requested with a height
of around .600 inch to accommodate
heavyweight bullets.

For those who might not be familiar with the Ruger 50th Anniversary New Model Blackhawk flattop .357 Magnum frame, it is similar in size to the Colt New Frontier (although slightly larger) and features a transfer bar safety, making it practical and safe to load six cartridges. It features a fully adjustable Micro rear sight, which combined with the flattop frame is attractive and considered a clean and classic look by single-action aficionados. This New Model frame was introduced in 2005 and features what Ruger refers to as an Indexing Pawl. This system is much more forgiving (when compared to previous New Model Blackhawk revolvers) in aligning chambers with the loading trough.

The steel grip frame is shaped similarly to the original Ruger Blackhawk flattop, featuring an aluminum XR3 grip frame that was used from 1955 to 1962 and is so popular today. It is thinner and measures .438 inch. Although not exact and notably heavier, it gives a similar feel to the Colt SA.

Incidentally, Lipsey’s requested a taller front sight than is found on the .44 Special counterpart. This allows sight in with heavier bullets of 285, 300 and even 320 grains. For those who will never use anything heavier than standard 250- or 260-grain bullets, the front sight can be milled shorter so that the rear sight body can be adjusted low or flush with the flattop frame.

Before beginning the shooting aspect of this article, primarily to assist in getting the most accuracy from these new sixguns, a set of Brownells/Wolff gunsprings (800-741-0015 or was installed on each that helped reduce factory pulls from 72 to 40 ounces (blue) and 76 to 44 ounces (stainless).

Ruger top straps and rear sight combinations (left to right): New Model Blackhawk .357 Magnum with “ears” that
help hold the rear sight in its channel, New Vaquero .45 Colt with fixed sights, original 1956-era
Blackhawk .357 Magnum with flattop frame and Micro rear sight and Lipsey’s New Model Blackhawk
.45 with flatttop frame and Micro rear sight.

I have received calls from fellow gun writers, several from friends and readers, and even Lipsey’s wanting to know what pressure levels I consider reasonable for these sixguns. Measuring web and chamber wall thickness, especially just over the bolt notch, is an indicator, but additionally I placed a call to Ruger and asked if .45 ACP +P ammunition is acceptable for that cylinder and was told it should be no problem. The .45 ACP cylinder walls are almost dimensionally identical to the .45 Colt with similar strength. The .45 ACP +P cartridge has an industry maximum average pressure rating of 23,000 psi and is the figure I consider 100 percent safe in the .45 Colt cylinder. When the .45 Colt is loaded to this pressure level, it offers substantial performance and is capable of pushing 250-grain jacketed bullets 1,100 fps, 280-grain cast bullets 1,150 fps or 318-grain versions 1,070 fps.

The “warning and instruction manual” roll-mark is located on the bottom of the barrel.

The above loads offer enough performance to take deer, elk, moose, black or even grizzly bears, but it is important to match the correct bullet to the game being hunted. Only a small percentage of shooters will want more power, and for those it is suggested to purchase a Ruger New Model Blackhawk .45 Colt built on the larger .44 frame, which will digest loads up to 32,000 CUP and will easily out-step the .44 Magnum. It should also be emphasized that handload data published for Ruger Blackhawks and New Model Blackhawks chambered in .45 Colt that are built on the larger .44 frame is not suitable and should never be used in this .357- or medium-frame .45.

Although handload data was primarily developed in a Lipsey’s Blackhawk .45 Colt
with a 51⁄2-inch barrel and blued steel, many loads were also shot in a stainless steel version
fitted with a 45⁄8-inch barrel.

For those who don’t need +P- type performance, I have included many standard pressure loads that are within industry pressure guidelines of 14,000 psi. This data contains loads that are suitable for defense, hunting, cowboy competition or general-purpose appli­cations and utilize a variety of bullet weights and styles. In spite of being within industry pressure standards, many offer a substantial performance improvement over factory loads. Most factory loads are well below industry standards due to the many black-powder-era Colt Single Action Army revolvers and other comparatively weak fire­arms still in use. Frankly, black-powder guns (often constructed of comparatively weak iron or soft steels) should not be used with any smokeless powder loads!

A variety of factory loads was shot in the Lipsey’s Blackhawk .45 Colt.

After removing packing oil from the chambers and bore of the 5½-inch barrel, I settled down in a seated back position to sight it in. After some minor sight adjustments and using a handload containing Starline cases, 255-grain cast bullets from Lyman mould 454190 and 9.0 grains of Alliant Power Pistol capped with a CCI 300 primer, the first group measured 1.5 inches.

Next, factory loads were used to check for accuracy and velocity. These consisted of traditional Remington and Winchester 250- and 255-grain hollowbase, swaged lead bullet loads at an advertised 860 fps, which were the real cowboy loads, being more or less in continuous production since around 1900 in smokeless powder versions, or 1873 with black. Additionally, loads containing swaged, cast lead and jacketed versions intended specifically for self-defense applications were tried. Overall accuracy of all factory loads was satisfactory.

In addition to hand-cast bullets, a variety of commercial bullets were used to develop data for the .45 Colt.

Although space will not allow much discussion of .45 ACP performance or handloading, select factory loads were tried in both revolvers. Overall accuracy was good, with each revolver proving capable of groups hovering around one inch at 25 yards with select loads. Using only 230-grain bullets, the 5½-inch barreled sixgun churned up average velocities from 807 to 913 fps, with the latter figure being produced by Winchester’s Supreme Bonded PDX1 JHP.
RCBS carbide dies were used to size and expand new Starline cases. Expander balls measured .449 inch for jacketed bullets and .450 inch for cast and lead bullets. A Lyman roll crimp die was used to seat and crimp bullets. The crimp was adjusted to best suit each bullet but was generally as heavy as the crimp groove or cannelure would allow.

Several powders were used in loads for both revolvers.

A couple of loads are listed with the Hornady 200-grain HP-XTP that is designed without a crimp cannelure for the .45 ACP. A cannelure can be placed on this bullet, or any jacketed .45 ACP bullet, using a CH cannelure tool. Another option that I prefer is to use a taper crimp die that will hold bullets in place during recoil of any standard pressure loads and will provide enough bullet pull to assist with proper ignition. Although the above Hornady 200-grain bullet was the only .45 ACP bullet used, I have successfully taper crimped many 230-grain .45 ACP bullets in .45 Colt cases, including the Speer Gold Dot and Hornady HP-XTP. Data for the Speer 225-grain JHP bullet may be interchanged with the above 230-grain .45 ACP bullets.

Due to their quality, uniform overall length (for consistent crimp) and notable strength, Starline cases were used exclusively.

It should be noted that they produce less chamber pressure (stoked with identical loads) than most other cases. They are available factory direct at 1-800-280-6660.

RCBS and Lyman dies were used to assemble handloaded ammunition.

Large pistol primers will offer proper ignition with any of the powder and bullet combinations used in the accompanying data, with CCI 300s being used exclusively. The only exception being Hodgdon H-110 powder, which was only used with the 318-grain cast bullet from Lyman mould 454629. When matched with a heavy-for-caliber bullet, it will ignite easily and offers uniform velocities with a standard nonmagnum primer. On the other hand, in extremely cold temperatures, I have seen this powder squib, barely generating enough pressure to get the bullet out the barrel! For these reasons I always suggest a magnum primer, such as the Federal 155, when loading H-110.

Cast and lead .45-caliber bullets included: (1) Oregon Trail 200-grain RNFP, (2) Rim Rock 225-grain DEWC,
(3) 225-grain cast RCBS mould 45-225-CAV, (4) Speer 250-grain lead SEC, (5) Oregon Trail 250-grain RNFP,
(6) Hornady 255-grain lead FP, (7) Rim Rock cast SWC GC, (8) Lyman 255-grain cast mould 454190,
(9) Lyman 255-grain cast 454424, (10) SSK 263-grain cast mould 270-451, (11) RCBS 280-grain cast mould
45-270-SAA and (12) Lyman 318-grain cast mould 454629.

It is always interesting how a cartridge changes personalities based on bullet choice, with the .45 Colt being a great example. There are several jacketed bullets that offer quick, reliable expansion, even on pests as small as jackrabbits, but also serve well for hunting deer-sized game and home defense. Examples include the Sierra 240-grain JHC, the Speer 250-grain Gold Dot HP, Hornady 250-grain HP-XTP and Nosler 250-grain JHP. In­ter­estingly, Speer, Nosler and Barnes bullets measure .451 inch, while the Sierra measures .4515 and the Hornady .452 inch. There were a number of loads tried (that were not necessarily included in the tables), and frankly there was very little difference in accuracy between the above bullets, with the Sierra and Hornady being tops and the Nosler and Speer being right on their heels. Each delivered enough accuracy that I would rather choose the bullet based on its terminal performance characteristics. With the correct load, each proved capable of 1.0- to 1.5-inch 25-yard groups. In spite of differences in their diameter, jacket materials and profiles, data can safely be interchanged as long as bullets are the same weight.

Two swaged lead bullets from Speer and Hornady were tried, which weighed 250 and 255 grains. The Speer .452-inch semiwadcutter was coated with a relatively new lubricant and resulted in little barrel leading at velocities of 850 to 900 fps. Accuracy was good. The Hornady bullet was a flatpoint profile, sized .454 inch and was cold swaged from 95 percent lead and 5 percent antimony. It was likewise accurate and produced minimal barrel leading at around 850 fps.

Jacketed bullets used to develop handload data included: (1) Speer 200-grain JHP, (2) Hornady 200-grain HP-XTP,
(3) Barnes 225-grain XPB, (4) Speer 225-grain JHP, (5) Hornady 240-grain XTP-MAG, (6) Sierra 240-grain JHC,
(7) Hornady 250-grain HP-XTP, (8) Nosler 250-grain JHP, (9) Speer 250-grain Gold Dot HP and (10) Speer 260-grain JHP.

Good cast bullets for the .45 Colt are legion, but there are a few noteworthy versions. Based on the Magma RNFP design, Oregon Trail Bullet Company (www offers 200- and 250-grain versions cast with exceptional quality and are a first-rate choice for the cowboy action shooter. Rim Rock Bullets ( has a 225-grain wadcutter, known as the DEWC, that has quickly become popular. It was tried at 50 yards where it proved accurate, and having a full-caliber meplat, it delivered incredible shock on game. Another interesting bullet from Rim Rock was a 255-grain SWC with a gas check that was cast with a Brinell hardness number (BHN) of 10 to 11, which has the potential to slug up in revolvers with larger throats. Accuracy was good and there was no harmful barrel leading.

The Lipsey’s Ruger New Model Blackhawk .45 Colt was accurate with a variety of loads.

A bullet that is often used in my ancient Colt SAs and likewise performs well in the Lipsey’s Ruger is from Lyman mould 454190, a 255-grain RNFP bullet that has a similar profile to nineteenth-century factory bullets. It is crimped over the ogive for an overall cartridge length of around 1.580 inches.

Another favorite includes bullets from RCBS mould 45-270-SAA, which from my alloy throws bullets at between 280 and 285 grains. It is effectively a modern Keith bullet with three driving bands, a single grease groove and a beveled crimp groove. The overall cartridge length (1.653 inches) is close to maximum for this Ruger .45 Colt, so be certain to use a sufficiently heavy crimp. Shot at 800 to 1,150 fps, it is a game-killing projectile and is accurate.

Another cast bullet that is noteworthy comes from Lyman mould 454629, originally designed by my old friend Dick Casull for his .454 Casull cartridge. It features a gas check (with Hornady crimp on versions being used here), three grease grooves, a meplat (aka flat point) measuring around .315 inch and weighs between 315 and 320 grains, depending on alloy. If I were to attempt moose or big bears, this would be a first-choice bullet. All cast bullets were sized to .452 inch, and it is suggested to fully size the front driving band to allow cartridges to chamber correctly in the Ruger .452-inch throats.

Brian considers maximum cartridge overall length to be around 1.6535 inches, or bullets
may “walk” out the end of the chambers and tie up the cylinder when subjected
to recoil. The load shown features a Lyman 318-grain cast bullet from mould 454629.

Regardless of bullet chosen, the maximum overall cartridge length should not exceed approximately 1.654 inches. This leaves about .012 inch before the bullet protrudes from the end of the cylinder, and since there will be some cartridge length “growth,” or bullets “walking” slightly during recoil, it is necessary to have that .012-inch margin of safety for reliability reasons.

Powder selection has grown, and today there are many outstanding choices. Some of the faster-burning powders that gave notably good results in terms of accuracy and low extreme spreads in standard pressure loads included Hodgdon Titegroup, Alliant Red Dot, Accurate No. 2 and IMR-700X. Notable medium burn rate powders included Alliant Power Pistol, Accurate No. 5, Hodgdon Longshot and Vihtavuori 3N37. In loads that exceeded industry pressure guidelines, with some data approaching 23,000 psi, outstanding powders included Hodgdon Longshot, H-110, Alliant Power Pistol, 2400, Accurate No. 9 and Vihta­vuori N350. Space will not allow a detailed discussion of my favorite bullets and loads, but satisfactory results should be obtained with each load listed.
As can be seen in the accompanying tables, these revolvers were fired extensively to develop data. After all shooting was completed, five factory loads were again tried for accuracy. In each instance, groups tightened notably when compared to groups obtained with identical loads when the revolver only had a few shots fired through it.