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High Pressure Loads for the .45 Colt

By Chuck Hawks

.45 Colt
Illustration courtesy of Hornady Mfg. Co.

For the purposes of this article, by "high pressure" I mean pressures above the industry accepted SAAMI maximum pressure limit. For the .45 Colt cartridge that is 14,000 psi as measured by the relatively new piezo-electric transducer method, or 15,900 cup as measured by the older copper crusher method. I will refer to all loads within the SAAMI limit as "standard pressure" loads.

I have read articles for and against the use of high pressure loads in the .45 Long Colt cartridge in the very strong Ruger Blackhawk SA revolver and Thompson/Center Contender break-action single shot pistol. I also have a shooting buddy who regularly shoots very high pressure loads in his Ruger Blackhawk Bisley Model, and we have discussed the wisdom of so doing on occasion.

I get e-mail questions on the subject of high pressure loads for the .45 Colt all the time. (There is a question/answer addressing this on my Handgun FAQ page.) In fact, I just completed a long e-mail exchange with a correspondent interested in purchasing a .45 LC gun, the second this week. Since there seems to be an ongoing interest in the subject, I have decided to address it in this article. My purpose is to present what I hope is a balanced and responsible view, not to promote or condemn the use of all such loads.

High Pressure .45 Colt +P factory loads

In recent years a couple of the smaller ammunition companies have introduced high pressure .45 Colt factory loads intended only for use in extra strong, modern guns. Perhaps the best known of these companies is Cor-Bon. Cor-Bon offers three high pressure loads in .45 Colt Caliber. Such Cor-Bon ammunition boxes are clearly marked ".45 Colt Magnum +P." There is, of course, no such caliber. These cartridges will chamber and can be fired in any .45 Colt revolver, although they are not safe in the majority of such revolvers.

Briefly, the Cor-Bon ".45 Colt Magnum +P" loads are as follows (Cor-Bon figures). First is a 265 grain Bonded-Core Hollow Point bullet at a muzzle velocity (MV) of 1350 fps and muzzle enerby (ME) of 1073 ft. lbs. The second high pressure Cor-Bon load is uses a 300 grain Jacketed Soft Point bullet at a MV of 1300 fps and ME of 1126 ft. lbs. The third load uses a 335 grain Hard Cast lead bullet at a MV of 1050 fps and ME of 820.3 ft. lbs.

I found the following warning about these loads on the Cor-Bon web page:
"This is NOT plinking ammo, this load should only be used in those guns that have the steel to handle the power. Guns in .45 Colt that are built on heavy duty frames, such as the Ruger, Freedom Arms, Colt Anaconda, and Thompson-Center Contender will handle this load with authority. This load is NOT intended for handguns such as older Smith & Wesson, Colt Single Action Army, or the Colt clones imported single action revolvers. Common sense needs to prevail! THIS IS NOT COWBOY AMMO!"

High pressure handloads for the Blackhawk and Contender pistols

Some (not all) of the major reloading manuals list two categories of .45 Colt loads. The first category contains loads within the 14,000 psi (or 15,900 cup) SAAMI maximum pressure limit. These loads are safe in all modern .45 Long Colt revolvers in good operating condition. The second .45 Colt section contains loads intended for use only in the Ruger Blackhawk revolver and T/C Contender single shot pistol. The Hornady, Sierra, and Speer reloading manuals have published the latter category of .45 Colt loads longer than most.

The reloading manuals that list these restricted loads are pretty coy about the actual pressures involved in such loads. The Hornady Handbook, 3rd Edition, says only that the pressures of their loads for the Ruger and T/C "are slightly higher than the earlier Colt revolvers or their replicas can withstand." These loads take the 250 grain Hornady JHP bullet to maximum muzzle velocities of 1300-1350 fps, depending on the kind of powder used. These velocities were measured in a 10" Contender barrel.

The Sierra Handgun Reloading Manual gives no indication as to the actual pressure of their high pressure loads, merely stating that they are intended solely for the Blackhawk and Contender pistols, and that even in those guns the .45 Colt "must not be crowded to very high pressure." The top Sierra loads drive a 240 grain JHP bullet to 1250 fps with either 16.9 grains of Blue Dot or 25.0 grains of Winchester 296 powder from the 7.5" barrel of a Ruger Blackhawk revolver.

The Speer Reloading Manual No. 13 gives more information than the other two about the actual pressure of their high pressure .45 Colt loads. It states that, "Loads for the 300 grain bullet were developed in a copper crusher test barrel; they operate at higher pressure than those for lighter bullets, up to 25,000 cup."

The maximum loads in the Speer Manual give MV's of 1343 fps with the Speer 225 grain bullet and 16.0 grains of Blue Dot powder, 1183 fps with the 260 grain bullet and 20.5 grains of W-296 powder, and 1193 with the 300 grain bullet and W-296 powder. The Speer technicians used a Ruger Blackhawk revolver with a 7.5" barrel for velocity testing.

The Hornady loads, at first glance, seem to be the hottest. They list 19.9 grains of Alliant 2400 powder as giving their 250 grain bullet a MV of 1350 fps. But remember this is from the 10" barrel of a closed breech Contender. And the hardness of a bullet's jacket and core influences pressure. (The Hornady 250 grain bullet has a reputation as a relatively soft bullet.) The closest Speer load with the same powder (Alliant 2400) gives their 260 grain bullet in front of 18.0 grains a MV of 1156 fps from the Blackhawk revolver.

In my own chronograph testing, Remington 158 grain JSP .357 Magnum factory loads averaged 1580 fps from my 10" Contender and 1325 fps from my 6.5" Blackhawk revolver, so I suspect that most of the advantage shown by the Hornady load is due more to the test gun than the extra pressure provided by the additional 1.9 grains of powder.

The top Sierra load uses more powder but a lighter bullet, 25.0 grains of 296 behind a 240 grain bullet for 1250 fps. This seems like a pretty stiff load to me; the difference in velocity is probably more attributable to differences between chronographs than pressure. (No two chronographs seem to give identical results.)

Speer's top load for both the 260 and 300 grain bullets used Winchester 296 powder. But the maximum load for the 300 grain bullet (23.0 grains) used 2.5 grains more powder than the maximum load they used behind the 260 grain bullet. This is the exact reverse of what would normally be expected. They got 10 fps greater velocity with the 300 grain bullet than with the 260 grain bullet, also the opposite of what one would expect.

I can only conclude (as they did) that the loads for the 300 grain bullet were indeed the higher pressure loads. Further, I'd guess that the maximum pressure of that 300 grain bullet load was pretty close to the maximum pressure of the Hornady load for their 250 grain bullet or the Sierra load for their 240 grain bullet.

So I accept that Speer's 25,000 cup is indeed a reasonable maximum pressure for high pressure .45 Colt loads intended for use only in the Blackhawk revolver and Contender pistol. I would recommend that anyone loading high pressure loads for Blackhawk or Contender pistols limit them to 25,000 cup or, lacking pressure testing facilities, the maximum loads published in the Hornady, Sierra, and Speer manuals (depending on the bullet chosen). Other brands of bullets, even if of the same weight, must not be used with these loads as the bearing surface and hardness of the bullet have a significant effect on pressure.

A little simple arithmetic shows that a 25,000 cup load is slightly more than 57% above the 15,900 cup SAAMI maximum pressure for the .45 Colt cartridge. A 57% overload is a lot, more than a proof load! To load or advocate loading the .45 Colt cartridge to even higher pressure would appear to be irresponsible.

High pressure loads in other brands or models of guns

But what about other modern revolvers chambered for the .45 Colt cartridge? For many years Smith & Wesson built a .45 Colt DA revolver on their large "N" frame that looked nearly identical to their .44 Magnum Model 29. I have been asked specifically about this revolver in the past, as their owners sometimes conclude that if the Model 29 can withstand the 36,000 psi (43,500 cup) of a .44 Magnum cartridge, their revolvers should be able to withstand the same pressure. BUT THEY CANNOT!

The reason is that the Model 29 is made from special alloy steel specially heat treated to withstand .44 Magnum pressures. S&W themselves have put this in writing in their advertisements, and a talk with one of their technicians will confirm it. NEVER use any high pressure .45 Colt load in a S&W revolver. They are designed to handle standard pressure .45 Colt loads ONLY.

The original model Ruger Vaquero is a fixed sight variation of the Blackhawk and falls under the "Blackhawk" classification, as is the Ruger Bisley version of the Blackhawk. These are cosmetic variations capable of handling the same pressure as the standard Blackhawk, and fall under the general heading of "Ruger Blackhawk revolvers." The "New Model" Vaquero, introduced at the end of 2004 primarily for cowboy action shooters (who use only low pressure loads), is built on a smaller frame--much like a Colt SAA--and is not recommended for high pressure loads.

The authors of the major reloading manuals were aware that there are modern guns other than the Blackhawk and Contender that are chambered for the .45 Colt cartridge. These include not only the Colt Single Action Army, Colt Cowboy, and the various replicas thereof, but the DA Colt Anaconda, Ruger Redhawk, aforementioned "N" frame S&W, and others. But no exception is made for any of these guns, not even the excellent Anaconda and Redhawk. Clearly, FOR BLACKHAWK AND CONTENDER ONLY means just that!

The following quote is from the section of the Speer Reloading Manual No. 13 devoted to high pressure .45 Colt loads, and reinforces this point.

"IMPORTANT SAFETY NOTICE. These loads are intended for use only in Ruger Blackhawk and Vaquero revolvers, and the Thompson/Center Contender. They are not to be used in any other make or model of firearm!"

The Hornady Handbook, 3rd Edition prefaces their high pressure data with this simple statement: "The following data is to be used only in the T/C or the Ruger Blackhawk."

My copy of the Sierra Handgun Reloading Manual makes this blunt statement in the first paragraph of their section devoted to high pressure .45 Colt loads.

"The data on the following pages were developed for use in the Ruger Blackhawk and the Thompson/Center Contender pistol in .45 Colt caliber. Both of these pistols are of stronger construction than any of the other makes chambered for the .45 Colt cartridge."

Very high pressure loads

I understand and accept that the pressure safety margin built into any case is there for a reason. I also accept that the AMOUNT of safety margin may vary with application, that from an engineering standpoint it need not be, and probably is not, identical from cartridge to cartridge. Different cartridges are designed for different purposes, and may require different safety margins. The .45 Colt was designed as a self-defense cartridge, the .44 Magnum was designed as a high velocity hunting cartridge. There is no reason why the .45 Colt and the .44 Magnum cartridges should have same pressure safety margin. This is a point that seems to escape some proponents of very high pressure .45 Colt loads, who argue that if the .44 Mag. can be loaded to "X" amount of pressure with an adequate safety margin, so can the .45 Colt.

To use an analogy, I have been told by a friend who is very active in bicycle racing circles that bicycle tires are generally designed for 100% over-pressure. But I don't ride my 90 psi tires at 141 psi (57% above rated pressure) just because they are probably good to 180 psi. That seemingly large safety margin is there for a reason. Rubber, tire pumps, tire gauges, inner tubes (which perform a sealing function much like cartridge cases), valve stems, rims, air temperature, bicycle weight, rider weight, gross vehicle weight, riding style, road surfaces, and so forth all vary. I don't ride on a prepared track; I ride on city streets and bike paths. What if I hit a bump, which momentarily increases pressure?

Reloading, firearm, and environmental components vary, too. Air temperature and density, bullets, powder lots, primers, cases, crimp pressures, powder measures, powder scales, chambers, barrels, barrel and chamber temperature, and so on are all variables that can affect pressure. The world that we hunt and shoot in is not the same as the controlled environment of a ballistics laboratory, and our Blackhawk and Contender pistols are not manufactured to the same strength and tolerances as a pressure test gun.

The following quote from the section of the Speer Reloading Manual No. 13 devoted to high pressure .45 Colt loads for the Blackhawk and Contender addresses this point.

"IMPORTANT SAFETY NOTICE. Do not substitute components, or try to load higher than the data presented."

These safety warnings are not without reason. For example, what if I get a can of powder that produces greater than normal pressure? This is not hypothetical, as I have actually had it happen. I was chronographing .357 loads with a new lot (but familiar brand) of powder that gave an average instrumental velocity of 1365 fps from what were supposed to be 1000 fps loads. These happened to be hand measured test loads, and the unexpected velocity was consistent, not caused by an inadvertent double charge or something like that. (I might mention that I have never had a problem of any kind with any of my reloads for any caliber of pistol or rifle.) I fired 5 shots over the chronograph and immediately discontinued testing. That powder was withdrawn from the market, by the way.

I was probably getting pressure well above double what it should have been. I was testing what were intended to be mid-range loads in a .357 Mag. Blackhawk, so no harm was done. But what if I had been loading SAAMI maximum pressure loads? Then those hot powder loads might have been right around the yield point of my gun's cylinder. Maybe it would have stayed together, and maybe not. Now consider what would have happened if I had been bold (and imprudent) enough to load reloads that were intentionally 50% over pressure? It would have almost certainly taken even a Blackhawk apart. I would probably be shooting left handed today, and maybe blind to boot.

The point is, be satisfied with the high pressure loads listed in the Hornady, Sierra, and Speer manuals. They are plenty enough for the .45 Colt.

The strength of .45 Long Colt cases

The following is a direct quote from the Sierra Reloading Manual.

"Although it has internal capacity comparable to that of the .44 Magnum, the thickness and strength of the .45 Colt cartridge case is much less than that of the .44 Magnum, imposing a limiting factor upon the older cartridge which cannot be avoided."

And this is a quote from the Speer Reloading Manual.

"Some handloaders have assembled .45 Colt loads that exceed the pressures of the .44 Magnum! The .45 Colt case is not as strong as the .44 Magnum case and you must not attempt to load it as high, regardless of the gun model."

The following quote is again from the section of the Speer Reloading Manual devoted to high pressure .45 Colt loads for the Blackhawk and Contender.

"We recommend that these loads be used in new or once-fired cases known to be of recent manufacture."

That alone is enough commentary on the .45 Colt case to make me cautious, even if I hadn't read the other warnings. I can't recall ever reading any such caution regarding .357, .41, or .44 Magnum cases. I can tell you as an experienced reloader that I get much better case life from all .44 Magnum reloads than I do from standard pressure loads in .45 Colt brass.

Have you ever had a revolver case fail? I have, a .45 Long Colt case in fact. (Not in my gun or with my loads, though!) It was in a friend's gun with supposedly normal pressure handloads using 255 grain cast lead bullets. All I know is that he handed me his new gun to shoot a cylinder load of cartridges, and the 2nd cartridge I fired split from the mouth all the way down to the rim. The recoil from that shot felt like a high pressure load. At first I thought the gun had blown up. It made a heck of a bang, and sprayed my shooting hand with hot powder and bits of brass. But there was no lasting harm done to the gun or me. Its cylinder was not bulged or damaged in any way. If I remember correctly, it was an Italian-made Peacemaker replica, which did sour me on replicas, probably unfairly. I stick to Colt or Ruger revolvers for my personal use.

John Linebaugh is a gunsmith who is one of the best known proponents of very high pressure .45 Colt loads, and his principal business is modifying Ruger Blackhawk revolvers for use with such loads (and also re-manufacturing them for his line of proprietary revolver cartridges). I read an article by Mr. Linebaugh in which he claimed that Federal makes the best .45 Colt brass. He felt that Winchester was the second best brand, and that Remington brass was inferior to both.

I disagree with most of Mr. Linebaugh's assertions about very high pressure .45 Colt loads and the strength of the .45 Colt case in general, but I do agree with him about the superiority of Federal .45 Colt brass. Federal is the only brand of .45 Colt case that I currently reload. I gave up on Winchester brass because the boxes I tried were so brittle that they started developing case mouth cracks (from roll crimping) after 2-3 reloads. These cases were used with standard pressure reloads only. As a result I threw away all of my Winchester .45 Colt brass. I cannot comment on Remington .45 Colt brass, as by happenstance I have never used enough of it to form an opinion.

In my experience, Winchester magnum brass will typically go 6 to 8 reloads (using the same type of roll crimp) before developing the small case mouth cracks I saw with their .45 brass after 2 reloads. Even Federal .45 Colt brass lasts only about half as long as magnum brass. Again, these case mouth splits come from the necessity to roll crimp revolver loads and not from excessive pressure or a defective cylinder. But they do not speak well for the durability of .45 Colt brass compared to magnum brass.

My approximately 10 years of experience reloading the .45 Colt and 35 years of experience reloading the .357 and .44 Magnum cartridges (in both Colt and Ruger revolvers) leaves me with the definite impression that .45 Colt brass is indeed weaker than magnum brass. It should be since the .44 Magnum operates at about 2.5 times the maximum SAAMI pressure of the .45 Colt.

It is a tribute to the quality of modern .45 Colt brass that it has proven safe (in Blackhawk and Contender guns only) with maximum pressures about 57% greater than the SAAMI limit. But as for asking it to contain pressure far beyond that, NO THANKS! Perhaps it can be done, but to me it seems analogous to driving a sports car at 150 miles per hour on bald tires. You could probably get away with that, too, but is it wise?

The .44 Magnum and .454 Casull as alternatives to the .45 Colt

If I wanted a .45 Magnum I would buy a .454 Casull revolver. Then I could safely reload the thing to any pressure level from the normal .45 Colt level up to true magnum pressures with complete confidence.

Another way to circumvent the entire issue would be to purchase a .44 Magnum revolver. There is nothing magical about .45 caliber bullets, although some folks seem to think that there is. Actually, I have never shot a .45 from a bench rest that could equal the accuracy of any of the .44 Magnums I have shot from a bench rest. For some reason the .44 Mag seems to be an exceptionally accurate cartridge. The Ruger Super Blackhawk .44 Magnum is the top of the line and a little bit nicer gun than a standard Blackhawk, anyway.

There is no question that a .44 Magnum can handle high pressure loads, as that is what it was designed for. It can also handle very light .44 Special-level loads and everything in-between.

So while the .45 Colt can perhaps approach the .44 Mag. in performance (with very hot over-pressure loads), the .44 can do the same thing at standard pressure with standard factory loads--which has got to be an advantage in anyone's book.

Both cartridges can handle the same range of bullet weights (usually from 200-300 grains in JHP hunting bullets), and the .44 Magnum's .429" bullet has better sectional density (for better penetration) in every bullet weight than the .452" bullet. There is also a better selection of .429" bullets for the handloader.

.44 Magnum brass is more widely available, cheaper (because it is discounted more due to higher sales volume), stronger, and lasts longer. At least I have never heard even the wildest .45 proponent claim that .45 Colt brass is more durable than .44 Mag. brass! So what's not to like about the .44 Mag?


Perhaps this final quote from the Speer Reloading Manual sums the whole issue up best.

"The loads Speer developed (for the .45LC Blackhawk and Contender) are roughly halfway between standard .45 Colt and .44 Magnum pressures. This results in a significant increase in energy, yet the loads were safe in Speer's test firearms. If you need more power than this, buy a .44 Magnum or a .454 Casull!"

My last bit of advice is that if you have or get a .45 Colt caliber Blackhawk or Contender pistol with the intention of developing high pressure handloads follow the guidelines in the major reloading manuals exactly. Use the same brand of primer, brass, bullet, and powder; do everything just as they did.

Stick with the major reloading manuals from bullet makers like Speer, Hornady and Sierra whose primary interest is your safety and who publish loads for specific bullets. Ignore any load you read about on the Internet (or anyplace else) that is in excess of SAAMI guidelines. All guns are different, and what is "safe" in one gun may be unsafe in another.

In any event, most amateur load developers don't know that their loads are actually safe, they only know that up to the last shot they fired nothing failed. The very next shot may blow their gun up! Some of these high pressure .45 Colt loads are way beyond the pressure of proof loads, and while a good gun can survive a cylinder load of proof loads, it was not built to withstand a continuous diet of such loads. Eventually something is going to break. I suspect that all that saves some of these guys and their guns is that they don't actually shoot enough of their super powerful loads to reach that point.

The loads in the Hornady, Sierra, and Speer manuals have been used in thousands of Ruger Blackhawk revolvers for many years without a problem, so it seems reasonable to accept that they represent a safe and practical maximum for .45 Colt cartridges to be fired only in Blackhawk revolvers and Contender pistols. Keep in mind that we are supposed to be enjoying a recreational activity, not performing death defying stunts. Good shooting!

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Copyright 2002, 2016 by Chuck Hawks. All rights reserved.