Welcome to Adiga Armory! While we generally try to steer clear of doing opinionated, controversial comparison topics on calibers, we felt that the hardy .41 Magnum deserved its day in court. The following presentation may not be for the faint of heart… especially if you love the 10mm Auto like we do, but live with the assumption that it gives you “.41 Magnum power in a semi-auto”. Being that we are long-time, die-hard fans of the 10mm Auto cartridge, we have always been curious where the 10mm = .41 mag notion originated, having heard the comparison thrown around for years by all sorts of folks; from average Joe’s on Internet comment sections, to gun shop staff, to the most highly-respected gun writers and industry experts out there.
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While our steamy bromance with the 10mm Auto has flourished over the years, we do like to “keep it real” with our expectations. That said, we have yet to find any data to support the 10mm = .41 Mag comparison. On the contrary, when comparing the two, they were not even close… unless of course you compared the most powerful 10mm load to the weakest, powder puff, starting load in .41 Magnum, which is a far cry from a real-world comparison. Lets start by taking a look at the load data for Accurate #9 pistol powder, as the 200g XTP over 12.5g of #9 has been our go-to 10mm defensive load for about a decade now. Not surprisingly, #9 is also a fantastic powder for rolling your own .41 Mags.
The published velocity of this load is 1170 feet per second [fps] and 608 foot/pounds [ft/lbs] of energy from a 5″ barrel. However, out of a 4.6″ Glock 20 barrel, real-world velocities of this load are around 1120 fps and 557 ft/lbs at the muzzle. Conversely, a 200g bullet over 16.9g of #9 in .41 Magnum has a published velocity of 1503 fps and 1003 ft/lbs from a 10″ test barrel. This yields a real-world velocity closer to 1350 fps and 809 ft/lbs of energy in a 5″ revolver. If comparing 5-inch barrel velocities, this constitutes a 15% increase in velocity and a 33% increase in muzzle energy.
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Now, you might be saying “how about hot-rod 10mm loads from companies like Double-Tap or Buffalo Bore… those will put me in .41 mag territory”. Well, not exactly… you see, everything is relative. The .41 Mag can also be hot-rodded to attain “ludicrous speed” velocities. And, when comparing hot-rod loads side-by-side, the disparity between the two cartridges becomes even wider. Lets take a look at Buffalo Bore’s awe-inspiring heavy “Outdoorsman” line as an example.
The 220g cast lead 10mm load produces an impressive 1140 fps out of a 4.6″ Glock 20 barrel. That is 635 ft/lbs of energy at the muzzle. Very nice to say the least! However, the Buffalo Bore 230g cast lead .41 Mag load produces a massive 1370 fps out of just a 4″ revolver, or a 20% increase in velocity with a 10g increase in mass. That equates to a whopping 959 ft/lbs of energy, or a 51% increase over the comparable 10mm load.
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Based on this hot-rod comparison, a .308 Winchester is ballistically closer to a .300 Weatherby Magnum [the granddaddy of .30 cal magnums] than the 10mm is to the .41 Mag. When looking at standard, 180g .308 Win and .300 Wby Mag loads, we find a roughly 1096 ft/lbs [or 38%] difference in muzzle energy. In other words, it becomes a big stretch of the imagination to say the two are producing “similar” results. Yet somehow, the 10mm Auto is assumed to be on par with the .41 Mag, despite a potential 51% increase in power from the .41.
A more accurate comparison would be to par the 10mm Auto to a full-house .357 Magnum in a 5″-6″ barrel. As you can see, the .357 Magnum produces ballistics that more closely compare to the 10mm Auto. Having said that, 10mm fans should not feel down and blue. The .357 Mag is arguably one of the best man-stoppers in the handgun world. And, with the right load, it makes a very capable backwoods defense cartridge. Having 15+1 rounds of .357 Mag power in a semi-auto G20 is nothing to feel short-changed about.
Using the aforementioned Accurate #9 load data, we can see that the 180g XTP over 12g of #9 in .357 Mag produces a respectable 1202 fps, or 578 ft/lbs of energy from a 6″ barrel. The same 180g XTP load with 13.5g of #9 in 10mm produces 1242 from a 5″ barrel, and 617 ft/lbs energy. This is only a ~3% difference in velocity and a ~7% difference in muzzle energy. Unlike the 10mm to .41 Mag comparison, these results are close enough to be considered truly negligible.
Again, if we compare the hot-rod loads from each caliber, we see that the .357 Magnum can also be “rodded” pretty hot, causing another disparity with the 10mm to develop.
The 180g .357 Mag Buffalo Bore “Outdoorsman” load produces 1398 fps from a 5″ revolver, or 781 ft/lbs of energy. The similar 220g 10mm “Outdoorsman” load pushes 1140 fps out of a 4.6″ Glock 20 barrel, for a solid 635 ft/lbs of energy at the muzzle. In this scenario, the .357 Mag displays a 22% increase in muzzle energy, but also has a 40g decrease in bullet mass as well as decreased sectional density [SD]. While significant in terms of increased energy, the drop in bullet mass and SD means they are still in the same ball park when it comes to actual terminal ballistic performance.
CONCLUSION:
While we only covered a small portion of the available load data for these cartridges, it gives us a glimpse into what is quite apparent across the ballistic spectrum; that the 10mm Auto is not equal to the .41 Magnum. Perhaps the old saying “A Lie Repeated Often Enough Becomes Accepted Truth” holds firm.
Perhaps someone, somewhere, at sometime, in some long lost 1980’s marketing pitch stated that “the 10mm Auto will put .41 Magnum power into a semi-auto platform”, and it was repeated and parroted enough times that it became the “truth”. Who knows? While not everyone will be disillusioned by the data presented, it certainly ought to make food for thought. Either way, we didn’t want our love for the 10mm to blind us into believing it is something its not.
That said, we would love to hear your opinions on this subject. Thanks again for visiting Adiga Armory. Have fun and stay safe!
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How about in the 6 inch barrel of a Glock 40?
I read and believed all the hype from trusted gun writers concerning the 10mm. I got a fantastic buy for a Rock Island FS and totally was impressed with the gun. That gun shoots really well, but the loads I find for it simply do not add up to the hype the round was given. Being a .44 mag fan, I was a tad bit let down. Not sure what most write about “simular to the .41 mag..” but they sure did not have their facts quite right. This article renews my faith in those who give us “the facts”. All is well that ends well….came up with a load on my bench (blue dot) that is a tad bit more warm then what I get in the store. The gun shoots it well and is a bunch of fun. I am hopeful that more writers will take close note to how this writer gave us the facts/truth without the hype. Sad is it not the mis information sent by those we in the fields should be able to trust. Good article, thanks.
MANY OF THE SMARTER GUIDES CARRY A 12 GA SHOTGUN IN GRIZ
COUNTRY. IT JUST DEPENDS ON WHAT YOU THINK IS BEST WHEN YOUR LIFE IS AT STAKE.
So do Alaska State Troopers, with Breneke Black Magic slugs.
AA#9 is not a great powder for the 10mm. Blue Dot is the go-to for good performance, especially with 180 – 200 grain bullets. The .41 Magnum will still beat it a bit, but a 180 grain bullet at 1250 – 1300 fps from the 10mm makes the it more a distinction without difference comparison. The .41 will get you 1400 – 1500 depending on barrel length, and the 10mm gives you 16 rounds instead of 6. It’s really a toss-up between them.
So if the 10 is that much less than the great 41 how does the 10 compare to the 357 mg?
It actually compares quite well to the .357 Mag… we did a full video on this here: https://youtu.be/5Sd9Q0mmz4Q
I just appreciate the author using the term “ludicrous speed”! Too soon, people won’t understand where that came from. Keep up the good work.
What really will stick under the skin of the 10mm crowd is that not only is the 10mm quite far from a .41 Mag in performance, it’s actually much much MUCH closer to .40 S&W. I’ve loaded them all up and I’ve ran a 265gr @ 1550+ from a Blackhawk .41 Mag. Compare that to a G20 (with 5″ KKM bbl) running a 180gr @ 1375 fps vs. a Glock 35 (w.5.3″ KKM bbl) running the same 180gr @ 1325 fps.
Original Norma 10mm loads were 220 gr @ 1250 fps…factory ammo 5″ test barrel. Norma did not publish their spec to SAAMI, and loaded based on CUP instead of PSI.
If you can find the original load recipe, it was likely Accurate #7, because #9 had not been made yet, and it was loaded coal boiler pipe hot in a S&W 610 revolver.
The current spec is SAAMI load specs, which were later submitted for auto loading pistols, and achieve similar ballistics to old FBI loads with 20-40 gr lighter bullets.
Also, if anyone thinks they are loading 10mm hot, but get anywhere close with a .40S&W load, you are doing it wrong. My 6″ 1911 will will run 220 @ 1250-1300, but my brass begins stretching too thin after about 4 reloads. Looking at trying nosler brass to see if results improve.
.41 Mag has a slight edge, sure, but in this case 10mm literally was “good enough for government work” at the FBI after the notorious Miami shootout. Jeff Cooper’s goal for 10mm was to “mimic .41 mag”
The 41 mag is under appreciated. With the development of 41 Special, makes this caliber a more versatile round. Remember this caliber is a mid caliber magnum that fits between the357 mag and 44 mag. The 44 mag is a great round but prefer the handling capabilities of the 41 mag. As always, shoot what you enjoy and can handle. I have never met a caliber I did not like and appreciate the many choices we have in the shooting sports.
The .41 Mag does indeed have a small edge over the 10mm Auto, around 200 – 300 fps – in barrels of the same length, including the cylinder on the revolver. A 4.6 inch auto barrel is the same in usable projectile travel length as a 3 inch revolver. Put the 10mm into a 4-inch revolver and the difference between it and the .41 Mag narrow considerably.
Wrong! Would you rather be hit by a Mini Cooper or a bus traveling at the same speed?
Charles, I get your point and have heard that argument before. But it doesn’t really hit home for me… I would not want to get shot by a BB gun… but it doesn’t mean I will roll over and die if it happens. If that is the case then we would all be carrying .22LR for every purpose… technically it can kill pretty much any land animal in North America with a well-placed shot.
Anyway, I think the point of all this is that 10mm is not ballistically equal to .41 Mag… I don’t think anyone is trying to dictate to you what caliber to carry for your own needs.
I own a Springfield XDM 10 with a 5.2 inch barrel and a Blackhawk 41 with a 4&5/8 barrel. I reload for both. There is no doubt in my military mind that the 41 hits harder. One gun is for wearing in the woods, the other is for town. The 10mm is a great man stopper. The 41 with the right load will handle a bear. Each has it”s place and they are not interchangeable. I do not want a revolver in combat. Would a 15 shot 10mm stop a bear, probably, but the 41 would be more efficient.
It may not be a .41 mag but it’s close in true Norma form..sure, you can hot load anything but remember many guides in Alaska carry a G20 for big Brown Bear protection. 15+1 controllable rounds of 10mm in the neighborhood of 41 mag beats 5 shots of anything.. If they feel comfortable with it, I feel very comfortable with it in the Appalachian mountains or anywhere else for that matter, as a woods wepon or for SD..