The .41 Colt Part I


The .41 Colt Part I

For probably the better part of three years now I’ve had a lingering interest in “fixing” the old .41 Colt. The .41 Colt is a really lovely old cartridge, and in its later longer-cased, inside lubricated bullet form, a true .38 with a .386” bullet (unlike the .38 Special, which uses .357/358” bullets). Curiously, once fired it becomes a true .40, but more on that in a moment. The version I’ll be discussing is known colloquially as the .41 Long Colt to separate it from an earlier shorter cased, heel based bullet loading that dates from 1877. The original .41 Colt used a bullet the same diameter as the case with a reduced “heel” to crimp into the case, just like the .22 rimfire, the .22 as an aside is also the only surviving heel base cartridge in manufacture today. This was already a design that was behind the times the moment it was released, with the .44 Russian of 1870 having featured an inside lubricated bullet (modern, the bullet being smaller diameter than the case and fitting inside it) for the better part of a decade already. Colt themselves had the inside lubricated .45 Colt of 1872, though the .41 didn’t benefit from this experience.

Trends in the industry inevitably moved away from outside lubricated bullets, the heel-based bullet designs where bullet lubricant was outside the case and prone to picking up grit and dirt, as well as gumming up anything it was carried in. By the mid 1890’s the .41 was still selling strong despite its drawbacks, ultimately it would become the fourth most produced Single Action Army revolver chambering, and Colt finally decided to modernize it; slightly anyhow. The original heel-based bullet had a .406”-408” diameter bullet, the same diameter as the case hence the “.41” designation with a roughly .386” heel to crimp into the case. Colt lengthened the case, and made the entire bullet .386” to fit inside the case, finally rendering the .41 an inside lubricated cartridge. Overall length was essentially the same as the earlier load, as the longer case simply enveloped more bullet. It really didn’t have much to hang its hat on calling itself a .41 anymore, however it would grow from a true .38 to a .40 on firing. Reason being, Colt never developed a proper bore of the .41’s own, mid-1890’s the ~.406-408” groove diameter barrels were discontinued and the ~.401” groove diameter of the .38-40 Winchester was adopted. This was likely to streamline production concerns seeing as no other cartridge uses a .385” groove barrel, which would be proper groove diameter for the inside lubricated .41 Colt.

The final challenge the .41 Colt faced was its chambers. The chambers were bored straight through at ~.412”, this is the chamber dimension of all three of the .41 Colt SAAs I’ve owned anyhow. The .41 never benefited from modern chamber design, with throats sized to the bullet (not that Colt is known for bullet-sized throats, bless them). The poor hollow base just discussed, sized at .386”, was required to jump up in diameter all the way to .412” to first fill the chamber, then swage down to .401” in the bore. Relying on very soft lead bullets with a massive hollow base, this strikingly farm-engineered process worked fairly well. As a stopgap measure, it kept the .41 in the running and they sold well into the 20th century, ammunition wouldn’t dwindle away until the Second World War. The .41 was popular on its merits: mild recoil, good penetration. Accuracy was never one of those merits, and would likely be the .41’s downfall, it seems nobody wished to adopt it and develop .385” groove barrels.

As mentioned, for several years, the thought of finally giving the .41 Colt its fair shake has been lingering in the back of my mind. The .41 has proven to me, as will be shown below, it can really shoot as you would expect a mild mannered, .38 Special-esque cartridge to. It is not however, easy to make that accuracy come about, and that is not the .41’s fault. First, I started my thinking expedition with bullet design. I reckoned by combining the features of the heel base bullet and the hollow base, using a thin .411” driving band up front outside the case, combined with the .386” hollow base bullet body and tail behind it I could improve things considerably. NEI Molds agreed to make my design should I desire it and was very helpful in chatting out the details. I held off on ordering as it still just didn’t feel like the solution I wanted, it was yet another stopgap measure for the .41. I also wasn’t the first to have this thought I later learned, having picked up chatter of such a custom mold on US forums.

Next I started fishing for a barrel maker who could cut me a custom .385” groove barrel, and found one; that barrel is on order. I am looking for a .38 Special cylinder to ream, with a custom reamer I have yet to design and order to give the .41 proper throats at .385”. The beauty, in my mind, of this system is the standard Rapine style hollow base .386” bullets I’m already using will work perfectly, and it will be safe to fire with any .41 Colt ammunition dating after the heel base era- not that you run into much! Just as these thoughts all came together, tinkering with my 1897 Colt Single Action Army .41, I struck a load that shoots like hell on fire despite all the short comings of the .41 as described above. I now find myself in the awkward position of refusing to touch this great .41 SAA that I have shooting so well, as it is completely original, and not particularly excited to go to all this effort on a non-antique SAA frame.

You see, Canada’s laws are peculiar when it comes to legal antique handguns, they must be in a non-prescribed chambering. The .45 Colt, .44-40, .38-40, both the -20’s, and more are all out and are treated as modern, registration-requiring, paperwork bound pistols regardless if they were made when Ulysses S. Grant was President and Jesse James had just robbed his very first train. That’s not a joke; a .45 Colt made in 1873 when Jesse James had barely cut his teeth as a bandit requires authorization to transport paperwork, a gun range membership (that’s the only place it can be “authorized” to travel too, as well), and owner licensing. .41’s gratefully, do not. This brings about a particular fondness for .41 in Canada, as we can own them with far less restriction than more common chamberings. It also spurs my interest in “fixing” the old .41. We’ll rewind to the very old present however with shooting my 1897 Single Action Army, as that interest in “fixing” it has now been challenged.


Handloading the .41


Trying five different powders and two bullets with a multitude of seating depth and crimp variations, I was searching for a load that would make the .41 do the impossible; shoot like a properly designed cartridge, smokeless. 6”-12” groups at 25 yards were the norm, from the curiously good condition SAA of mine over Titegroup, Universal, Trail Boss, Triple 7, and FFFg Goex. Yes, it would hit the bipedal and otherwise threats it was designed to stop even at 25 yards, but this revolver was in too good of shape to shoot like that, even though common sense told me that was as good as it gets and to be pleased with the 6” group loads with black powder. I was not pleased however, and wanted a smokeless load, so I mined my excel spreadsheet chronograph data for theories on improvements. I focused in on IMR Trail Boss, reasoning that I knew it had a rapid pressure spike to hopefully bump up the bullet diameter as required, and I guessed that its higher load density being a “fluffy” powder would assist somehow. Call me old fashioned but black powder expanded the hollow base to bore diameter reliably with a full case, so my cockeyed reasoning stood that more volume in the case was better. Yes… black powder and smokeless of any load densities share nearly nothing in common, still, it was the only theory I had.

20 grains of Goex FFFg under the 185 grain Rapine makes for a show.

My first attempt, shooting 185 grain bullets, didn’t work; 12” groups. Erratic velocities… almost certainly due to inconsistently expanding hollow bases: I had lows from 500 FPS to highs of 800 FPS with carefully individually measured powder charges over a few three cartridge test groups with minor tweaks between each. The next several variations by way of three cartridge experimental loading sessions also failed, though glimmers of hope were showing. I was evening out my velocities, as on a hunch I had focused on crimp, having found Trail Boss to be extremely crimp sensitive in the past; it needs a heavy one! I could barely ignite the stuff in hard-to-crimp round ball .455 Colt loads for another antique SAA but that’s another story. I had produced a single good mid-600’s FPS shot string over my preferred weight of Trail Boss, using the 185 grain Rapine hollow base in soft lead. Velocity was too low, and I wasn’t expecting much from the group. I was pleasantly surprised however to find the tightest 25 yard group yet. I always shoot handguns at 25 yards when testing for accuracy, anything closer seems a lot like a waste of time for me unless we’re talking pocket pistols, but as my Beretta 950 review shows I even test those at 25 yards! Reason being, if you can shoot it accurately at 25 yards, you can at 7. The inverse is not nearly as often true.

Next I decided a shorter overall length / deeper seating depth was likely to help me, as it increases pressure, and I hoped higher initial pressure combined with the aggressive crimp you can achieve crimping over the bullet ogive might just get those bullets to reliably bump up to .412” over smokeless. The .41 Colt, nearly always chambered in very fragile guns with the slight exception of the SAA (antique SAA’s still aren’t strong, they’re just much stronger than the other antique .41’s) is very low pressure by virtue of its large .412” throats and soft lead bullets. The main pressure spike after initial ignition of the powder would occur as the bullet swages down to .401” in the forcing cone (as another aside, many .41’s don’t have true forcing cones, just a chamfered barrel) and fortunately the barrel-cylinder gap provides a pressure vent soon as the tail of the bullet leaves the cylinder. This by no means is to say the .41 is user friendly with pressure or you don’t need to worry about it, but it is a help to those of us loading the sparsely data-trailed old girl in SAAs. Back to the point, a short seating depth- very short, and a heavy over the ogive crimp evened velocities out at the 750 FPS mark and provided a stunning 1 ½” 25 yard group that dropped my jaw. Walking up to the target board, I was in shock seeing a cluster the size of a golf ball after days of 6 and 12” patterns, and it happened so quickly.


Recovered .41 Colt bullets bumped up full-length, even the frontal bearing area, to my bore’s .402″ from .386″.

Further testing would show crimp was the answer, and this was as much a function of the powder I chose to experiment further with as the .41 Colt itself. A fan of the 202 grain bullet, I experimented the same way with it and found stellar accuracy there as well, but with a more conventional looking cartridge as the slightly longer bullet makes the seating depth appear less drastic. While the 202 grain would not match the deep seated 185 grain’s stellar accuracy, it provided tight groups of its own and more consistent velocities. I found I could seat the bullet further out as well, likely due to the slight weight increase increasing pressure (I run the 202 grain over the same powder charge as the 185 grain) even with a less drastic seating depth. Pressure is definitely higher, as the 202 grain ran the same velocity over the same powder charge as the 185 grain in my load and gun, 750 FPS or a tad more. As mentioned the velocities were much more consistent than the 185 grain however, indicating better powder burn. I stuck with the 202 grain loading as consistency means a good deal to me in a load and the accuracy is plenty good enough, beating many of the modern handguns I do and have owned. Plus, it’s more powerful.

Now with fifty loaded cartridges of a specification my gun really likes, and performance as good as I can ask of any revolver I am at an awkward crossroads with my project. I will still make the “.41 done right”, but just the same I’m enjoying how a cartridge with so much going against it can be made to work so well. I will need to locate a rough shape SAA for the frame, perhaps a second generation, and screw on my “fixed” .385” groove diameter barrel and install my custom reamed cylinder. The results will be interesting and I’ll no doubt write about them. I’m still struggling with the name for the new version of the .41 Colt, as it really won’t be anything near a .41 anymore. Current front running ideas for the name of my project are .38-41 Colt, .385 Colt, and .41 M-Colt (for Morrison / Modified). We’ll see which I settle on when my parts come together and what designation the barrel wears, I’m partial to the names that keep “41” in , and three digits of caliber in a designation is for rifles in my mind with regards to the .385. The only drain on my enthusiasm for the project is it is no longer likely to shoot any better than my original .41 Colt! Never thought that would happen.



IMR Trail Boss, 1.325” OAL with heavy roll crimp – Very Accurate, Very Consistent

202 grain Rapine soft lead

4.0 grains

750 FPS


IMR Trail Boss, VERY short OAL / deep seat – Superbly Accurate, Moderate Consistency

185 grain Rapine soft lead

4.0 grains

750 FPS


Hodgdon Titegroup, 1.35” OAL moderate roll crimp – Moderate Accuracy, Consistent

185 grain Rapine soft lead

4.0 grains

700 FPS


Omitted are the other three powders that I found unsuitable, and all the “bad” loads, whether that be inconsistent or inaccurate, it was usually both. Surprisingly I had poor performance from Hodgdon Triple 7 black FFFg powder substitute , with very inconsistent velocities.