USA – -(Ammoland.com)- The 10mm Auto, sometimes referred to as the “357 of the Auto Pistol World”, has experienced a resurgence of late. Since its development in the 1980s, the 10mm found sudden popularity only to stagnate and shrink, but now the 10 is back with more pistols and ammunition than ever before. With that increased popularity comes truths and myths surrounding the round . . .
Semi-automatic pistol rounds are generally power-limited. The size and shape of the round must fit into a practical grip. That limits how much lead and powder can be on board. Revolvers don’t have that problem and magnum cartridges have been the mainstay of handgun power since the beginning. But the 10mm promises magnum-like power in a semi-auto platform along with all the benefits of that platform: faster reloads, more ammunition before reloading, ect.
10mm Auto vs. 357 Magnum
There is talk about the 10 being as powerful as the 41 Magnum. This is all talk about pressure curves on a graph where the hottest 10mm met the lowest pressure 41 Magnum rounds. A fairer comparison for the 10mm is the original magnum cartridge, the 357 Magnum.
With that question in mind, it was time for my favorite past time—a ballistics gel test.
.357 Magnum A Brief History
By the 1920s, American law enforcement turned away from their various 32 caliber revolvers then common in service for the much more powerful 38 Special cartridge. Despite being high powered for its day, the 38 Special showed some weaknesses early in the Gangster-era. It didn’t always work when defeating obstacles like steel automobile bodies, auto glass, and surplus bullet proof vests worn by the up and coming motor bandits that used more force than finesse in their crimes.
Higher pressure 38 Special revolvers and larger handguns to handle the round resulted until it was decided to develop a brand-new cartridge, the slightly longer yet much more powerful 357 Magnum. The year was 1935 and it became the most powerful handgun cartridge of its time with a 158 grain bullet traveling at about 1400 feet per second. Magnum revolvers were favored by law enforcement for many years since until they were retired for increasingly reliable, higher capacity semi-automatic pistols. Even so, the 357 Magnum ammo remains popular and is a gold standard of handgun power.
10mm Auto Ammunition
As the magnum revolver was puffing along in the 1980s, there was a desire for a semi-automatic pistol with similar power. Thus the 10mm Auto was born, firing a 40 caliber bullet at the same speed as the 357 Magnum. In the aftermath of the 1986 Miami Shootout, the FBI sought to replace their 357 Magnum revolvers and lower-powered 9mm auto-pistols with the 10mm. It promised more power than the 9mm while being faster to reload than the revolvers in standard service at the time. It was found that the new 10mm pistols were hard to control and the round was downloaded and eventually necked down to make the 40 S&W round.
The 10mm fell into obscurity with few pistols and few ammunition makers producing for the round. But in 2018, demand is higher and the 10mm is finally getting its due as an excellent hunting and defensive cartridge.
The 357 Magnum and the 10mm Auto come in a variety of loadings, but the larger 40 caliber bullet of the 10mm affords it somewhat heavier projectiles in factory loads. The 10 is often found using 180 grain bullets while the 357 uses a 125 grain bullet. Heavy grain bear-type loads range up through 200 grains for the 10 and 180 with the 357, so there is much overlap.
10mm Auto vs. 357 Magnum : The Test
In our head to head contest, I selected the same brand of ammunition with as close to the same weight of bullet as possible. The guns selected are as close as possible in barrel length so as to not unfairly skew the results to one end of the camp to the other. Hornady offer’s their Custom line with a 158 grain XTP bullet for the 357 Magnum and a 155 grain XTP for the 10mm. While the 158 grain weight is fairly standard for a 357, the 155 grain bullet used in the 10mm is slightly light in its typical range.
The test firearms are the Glock 29 Gen 4 in 10mm and the Smith & Wesson Model 27 in 357 Magnum. The Glock sports a 3.77 inch barrel vs the 4 inch barrel on the Smith. This is as close as I could get in factory guns and ¼ of an inch won’t make much difference in velocity.
That was proven true when I fired both rounds through the chronograph on two separate occasions during two test runs of each ammunition. Despite having a shorter barrel, the 10mm was slightly faster.
Hornady Custom 10mm 155 grain XTP – 1345 feet per second
Hornady Custom 357 Magnum 158 grain XTP – 1264 feet per second
*five shot average of shots
On paper with these comparable loads, the 10mm is slightly faster with an 81 feet per second advantage. That is much when we are talking about handgun velocities. But how would that translate in ballistic gel?
I lined up a Clear Ballistics 10% ordinance gel block and got to work. The block was covered with four layers of denim, which is an FBI protocol. The optimal performance of a round is 12-18 inches of penetration to consider quartering shots, bone, ect. I started by firing the 357 Magnum round from close distance to assure a square hit. It zipped through the sixteen inch block. I needed to double up.
I added a second block, which caught the follow-up projectile. The 10mm had no such trouble as it was stopped in the first block.
The 10mm round expanded to .70 inch, flattening out impressively, and stopping at the 16 inch mark. The first five inches of its wound tract opened to an inch and a half before abruptly terminating into a straight path until the bullet came to rest.
The 357 Magnum’s smaller 9mm bullet mushroomed slightly to .54 inches and traversed 22 inches of gel. Both 357 Magnum tracts showed inch-wide cavities out to the first nine inches of the block.
The 357 Magnum over penetrated and did more damage further on than the 10mm, however the 10mm round dumped its energy into the first block with respectable damage just inside the entrance wound.
The 357 Magnum’s smaller diameter will make for an inherently longer projectile or higher ballistic coefficient. This allowed it to penetrate deeper despite its lower velocity. The greater penetration was also aided by the lack of deformation of the hollow-point due to that slightly lower velocity. The 10 performed as advertised and its extra velocity helped to flatten out the projectile.
So Who Wins?
We could go on to test a variety of different loadings of 10mm and 357 Magnum, but in this head to head taking into account as many variables to the experiment as possible what can be concluded is that both rounds live up to their respective reputations with much overlap between them depending on what load you choose.
After shooting both rounds through the chronograph, I was convinced that the 10mm would outperform the 357, given its velocity advantage with the same weight of bullet. What we got was a bullet that nearly doubled in diameter and violent expansion without overpenetration. The 357 exceeded the recommended maximum of eighteen inches.
However, it appears that the 357 Magnum’s damage was greater for a longer stretch of the wound than the 10. In the big picture, the 10mm will throw a slightly heavier bullet at the same speeds that the 357 will launch a lighter grain bullet. We can see in this head-to-head that the 10mm retains a very slight advantage in terms of energy, but the 357’s overall longer bullet gives it the edge for penetrating power.
The 10mm vs. 357 contest isn’t Mayweather vs McGregor. It is nearly too close to call—nearly. Like with any boxing match, there is more to the story and the opponents that is sometimes not taken into consideration.
It appears time is the 357’s best friend and why I give it the edge in the contest. You can find 357 Magnum revolvers readily—new and used. Any big box store that deals ammunition is bound to have 357 Magnum defensive ammunition. 10mm ammunition is hard to find and when you find it, it is often more expensive per box than 357s.
Many common 10mm loadings are weakly loaded compared to the round’s true potential and many off the shelf brands are seldom more powerful than the 40 S&W. Despite increasing demand, 10mm pistols are hard to find and they tend to cost a premium when found.
However, if you choose the 10 you gain the inherit advantages of automatic pistols, greater ammunition capacity and simpler reloads. No matter what platform you choose, I doubt you will be disappointed. Did I miss anything? Let me know which round you would choose in a 10mm Auto vs. 357 Magnum head to head?
About Terril Hebert:
Terril Hebert is a firearm writer native to south Louisiana. Under his motto-Guns, Never Politics-he tackles firearm and reloading topics both in print and on his Mark3smle YouTube channel, where he got his start. Terril has a soft spot for ballistics testing, pocket pistols, and French rifles. When he is not burning ammo, he is indulging his unhealthy wildlife photography obsession or working on his latest novel. Scourge of God, published in 2017. See more from Terril on youtube under Mark3smle
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Like I said, 2018 is “The Year of the 10mm!” TM. 😉
While the cartridges are similar in power the is no comparison in the capacity and weight categories. The G29 holds 10 + 1 and accepts the G20 15 round mags. The highest capacity in a 357 mag revolver is 8. The G29 is also much lighter. There are lightweight 357s but they aren’t as much fun to shoot and are still bulkier than a semi-auto.
Sorry. Should have compared a 125 gr or 135 g loading as well.
158 grain 357 loading are generally under powered compared to 125 loads.
158 g 357 are toward the heavy end. Factory 180g 357 are pretty pathetic in the velocity department.
Looking at one shot stops – the 125 grain 357 cant be beat , only equalled.
The FBI move to 10mm was a knee jerk reaction. Then when agents could handle the recoil of the 10mm, they had em down loaded. S&W said “we can get those velocities in a short 10mm” and the 40 was born.
Now, officers dont qualify well the 40, so the FBI decided new bullet technology has made the 9mm the perfect caliber.
Until the next Miami shootout ……. same as it ever was .
One (for lack of a better term) failure of the test was the bullet weights used. For the .357 magnum a 158 grain bullet is the heaviest standard load for the cartridge, in 10mm a 155 grain bullet is a light load for the cartridge. A better test would be a 158 grain .357 magnum vs a 180 grain 10mm, both are heavy for their cartridge.
The author could also benefit from learning the difference between ballistic coefficient and sectional density. BC is the one to use for external ballistics, not terminal. SD is the stat that mostly determines penetration. He should also research the date that “surplus bullet proof vests” became available on the market. Despite perhaps sounding good in his next novel, it wasn’t in the 1930s.
But this is a repost from another site, so its unlikely that he will even see these comments, much less care.
Full power load vs full power load would make for a better test than Hornady’s anemic loadings…
“There’s absolutely no reason to possess a semiautomatic, military-style rifle with large-capacity ammunition magazines except to kill lots of people within a few minutes.”
Which is why there’s one in every police cruiser, right? for killing lots of people.
I’ll just pre-emptively FLAME DELETE myself to save the moderator some time…
As 10mm gains traction 40s decent will accelerate as people with have the choice of capacity and ease of use over power and versatility with the 40 just kinda floating in the middle being just ok. With at least every type of pistol variant having at least one version of a 10mm cost and choice will cause 10mm to replace the 40 as one of the big three.
Google “search” does not mean what they want you to think it means, either.
I believe it’s .357Sig vs .357Magnum that you are supposed to be doing. More on 10mm vs .41Magnum please. Something that is never measured is the advantage of a wider bullet. The circumference alone opens up a greater bleed flow resulting in quicker deaths.
ding ding ding. no idea why we are comparing a larger caliber to essentially a high speed 9mm (yes yes, slightly different diameter). .357 SIG is in fact the “.357 magnum of semi autos”. but lets not get in the way of the 10mm love fest that seems never-ending.
If penetration is as written, I know which one I would prefer to carry for defense against bear. Deeper the better.
Robert, as your daughter’s teacher takes the class outside, your daughter may be forced to join them. Don’t think that teachers will all necessarily tolerate dissent. There will be peer pressure, disapproval, and outright orders to go along.
Remember, this is the left we’re talking about. And, they’re in full “emote, not reason” mode.
Ordered to a field trip without the parents consent?
I would bypass the school and go straight to the board of education.
Don’t have any teens yet, but I’d give them a choice: Either go to school, or spend the day doing nothing but manual labor. And when I mean day, I mean from sunup to sundown.
Hell, by the time March 14th rolls around, most of these dummies won’t even remember why they’re walking out of class.
THERE IS ONLY ONE WAY TO STOP THESE SENSELESS KILLINGS IN OUR SCHOOLS, ARMED AND TRAINED SECURITY GUARDS WITH CONCEALED FIREARMS TO TAKE DOWN THESE LUNATICS OR AT LEAST REDUCING THE NUMBER OF FATALITIES. NO OTHER WAY!!
Teachers who don’t show on that March 14 should be fired. No, if my kid was young enough to still be in school, she would be in school.
For defense against humans, this .357 load overpenetrates. It would have been interesting to see what a 125 grain bullet would do.
Totally off topic here, but has anyone else tried to call cornyn’s office? Every time I call it goes to voicemail.
I think he’s not answering the phones so that we have no way to complain about him going full gun grabber.
F’n coward.
If i need a semi auto with that kind of stopping power i will just get a deagle in .357. No need for a new cartridge. Dont care about the weight.
My kids aren’t teens. Both of my younger sons attend college but I guarantee they won’t do this stupid shite. My grandkids are homeschooled and I doubt they’d do this BS. BTW we had walkouts in HS protesting Vietnam…1970(?)
All my kids are now adults and beyond school age. But, if they were younger, I’d leave it up to them. The USA has a long and deep tradition of protest as part of the First Amendment, so I’d give them that opportunity to taste the rights that come with citizenship.
Of course, I’d also make sure they know that I’d be selling any firearms intended for their use should they participate in this protest. Because I would want them to learn that if you’re going to be in, you’re going to be 100% in.
That’s always been spring break in Texas anyway
I chose the 43. Only Glock I now own.
I get a much better grip on the 43 than I did the 26. I wear a large glove so YMMV.
I can shoot the 26 just about as well as the 43 but it takes more effort due to the grip (or lack thereof for me).
My son loves the 26 but hates the 43. Hands a re different.
Concealment-wise – the 43 is much easier for me to conceal and comfortable.
To me, the big advantage of the 26 is taking 19 and 17 magazines.
I would also purchase a Glock 19-sized pistol with a single stack – especially if it was a 40.
My 0.02.
And good thing he can open-carry that watch – it’s bigger than the danged pistol.
My wife likes the 27 for certain applications. Personally I find it way, way too small for my hand. It might work for me with an extended floorplate on the mag but I have not tried that yet.
If the school admin were smart, they would give everyone the day off, let them protest as they see fit. Then add an extra day at the end of the year like you would a snow day. Basically, if the kids feel strong and really want to protest, that is fine with me. They make their choice and pay the price for it, its a win/win situation.
By what authority will those new regulations be imposed?
Or is this just a delay tactic to come up with proposed regulations that will be discarded at a later date when things have simmered down?
The NRA’s ingenious strategy on full display.
Trump, Sessions, and the DOJ work for the NRA?
funny how things can change overnight
Trump just announce a ban on bump stocks and OpticsPlanet.com that have them for sale.
https://www.opticsplanet.com/slide-fire-solutions-brand.html
i wonder how many people who said will not give them a dime will jump at a chance to stock up on bump stocks before they are banned forever. 😉 yes, Trump is our 2A protector and Opticsplanet.com is the traitor
I don’t see how a ban on bump fire stocks would have to revolve around a baseline rate of fire. Why not make it targeted to the mechanism type instead? Seems relatively easy to me.
I got my PCR back from CGW two weeks ago and can say that the review here is absolutely true. David at CGW transformers good hunny I an exceptional weapon. I went with the Pro Package with a stainless guide rod and their fiber optic sights. The trigger on this thing is sweet!
Well, automatic weapons should not be restricted either.
OK really is OK. I love ‘ em. And they seem to last a lot longer than polymer. Mind you I have plastic, aluminum and even steel. But metal just seems more… durable.
We are too free! Please, government, take away our rights! We are not using them anyway (except for few old fat white guys and they don’t count).
Joe, who’s job is putting rings in hog’s snouts, must have been drunk again. Alcohol makes him miss a lot.
My .357 usually slings 125s GDs at 1695fps. They expand to .96″ (max) 6 pointed stars and stop between 11.5″ and 12.5″ in clear gel. It is a very different load than Terril’s. I also have 200gr hard casts that don’t expand and sail through 30-35″ of gel for different circumstances. The load can change the gel results wildly. .357 vs 10mm is a matter of taste more than anything else. If I knew for sure that I was going to get in a gun fight I”d probably choose a high capacity 10mm though.
Wow you learn something new everyday. Apparently according to the comments , ARs were never reliable until the Pmag came out due to everything else being shit mag wise. So does this mean AK fan boys are right and AR reliability issues did persist after the Vietnam era ballpowder/cleaning kits debacle? So ARs have only truly reached good reliability in the past few years due to all the money pit operator parts and unobtainium grade quality Pmags?
Reminder that the Original Children’s Crusade was a scam that led many kids to be kidnapped and enslaved, if they actually survived the journey in the first place.
Yeah like we need to give up rights based on the demands of soap eating teens who can’t figure out what bathroom to use.
Actually, I think the NRA should always just shut up and work behind the scenes when on “defense”. The people they would be responding to now don’t care one iota about facts and statistics.
They should only make public comments when things are quieter and they can be on “offense” pushing things like reciprocity, etc. without all the emotional screeching getting in the way.
From the way the story is portrayed, that guy did everything right, and did a huge solid for those people. Sounds like they were about to dip out, the husband caught wind of it, and hightailed it to stop them before they left.
Forgive my lack of caring for a piece of dog shit that beats his own kid with a pistol. Good riddance.
Slightly on topic:
If Wayne LaPierre — or any other representative of the NRA — had any guts, they would appear on TV talk shows in Washington DC and hold up a 30-round AR magazine.
Yes, there is a risk of getting arrested for violating the district’s ban. But they could — and should invoke the David Gregory defense.
http://cdn0.thetruthaboutguns.com/wp-content/uploads/2013/01/David-Gregory-with-the-offending-magazine-courtesy-seattlepi.com_.jpg
This country’s messed up idea of adulthood makes me crazy.
16 to drive (varies)
18 to be an “adult” sign contracts, join the military
21 to drink….
Its just crazy. Pick an age as “adult” and stop.
26 to be removed from parent’s family healthcare plans…
The reason 16 is the age for driving is because 16 is the age for minimum wage labor at coffee shops, fast food resturants, etc. They want those kids out their doing work, but I don’t like the idea of 16 year olds driving myself, I’d raise that to 18.
18 for most everything.
21 for alcohol.
Where do guns fit in? IDK, but we already have 21 for handguns and that doesn’t seem to be opposed, though it should because 18-20 year old women are most likely to be sexually assaulted. I would say 21 for semi automatic weapons. 18-20 year olds can still defend themselves and hunt with pump shotguns and lever/bolt action rifles.
I don’t think all rifles and guns should be restricted until 21. That’s doesn’t make sense.
357 Magnum isn’t what it used to be. 1264 fps is weak for a 158 grain bullet. The original load was a 158 grain lead swc at well over 1500 fps. Current ammo is loaded to around 33,000 psi. The original 10mm load was a 200 grain bullet at just under 1200 fps, but that load was beating up the guns pretty good. In reality the 10mm and 357 Magnum are ballistic twins from a handgun with the hottest loads being about equal. I like them both.