10mm Auto vs. 357 Magnum Ammunition : Ballistic Gel Test Results ~VIDEO

Terril wants to know which is better, 10mm Auto vs. 357 Magnum , keep reading to see his simple ballistic test results with off the shelf clear gelitain.

10mm Auto vs. 357 Magnum
10mm Auto vs. 357 Magnum

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

Glock 29 Gen 4 and the Smith & Wesson Model 27
The test subjects: The Glock 29 Gen 4 in 10mm and the Smith & Wesson Model 27 with 3.77 and 4.0 inch barrels respectively.

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 fun 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 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 : My Non-Scientific 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.

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. 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.

357 Magnum Wound Track
357 Magnum Wound Track : The 357 Magnum traversed into the second backup block, stopping at twenty-two inches.
10mm wound track
While the 10mm wound track (middle) is more pronounced, it doesn’t extend as far as the 357 Magnum.
The 10mm came to rest, in both my tests, at sixteen inches
The 10mm came to rest, in both my tests, at sixteen inches

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?

.357 and 10mm wound channels
.357 (top & bottom) and 10mm (center) wound channels: The fired projectiles expanded very well, but the 10mm’s added velocity helped it flatten out more. Fans of “big holes” rejoice.
.357 and 10mm wound channels and extra gelatin block
.357 and 10mm wound channels and extra gelatin block : 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.

We could go on to test a variety of different loadings of 10mm and 357 Magnum, but in this admitadley simple head to head test taking into account 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?


Terril Hebert
Terril Hebert

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.

  • 71 thoughts on “10mm Auto vs. 357 Magnum Ammunition : Ballistic Gel Test Results ~VIDEO

    1. The 10mm has the ability to shoot heavier bullets that should, by momentum, penetrate further and cause more disruption. Why compare similar weight bullets to see which is more effective within 2 separate calibers? Without getting into boutique ammo, why not compare the best of both to see which is more effective (ie. 180 or 200 grain 10mm vs. 158 grain .357)? The author appears to have done a thorough job within the confines of his testing, but this is like comparing the .270 and .30-06, then limiting the ’06 to 150 grains to make all factors equal. Gun calibers are not equal. True testing would be best vs. best.

      1. This is a good point because equal bullet weight with different diameter means different sectional density. If you compare penetration without first comparing sectional density, you are an idiot. Sectional density is the factor that should be constant not weight when looking at penitration. By comparing velocity and weight you can mathematically determine which delivers more energy. Additionally, I’m not certain what ammo from the same manufacturer is supposed to imply but if it is that both loads are identical other than caliber, I doubt that is the case. So many variables go into design of caliber specific cartridges not simply maximum pressure or type of powder.

    2. Proper comparison would between the most common cartridge loadings per caliber. The 357 is proper…10mm not so much. The reality, each caliber is most efficient at common loads with common weight pills, usually. At the very least the comparison…such have included 180grain for the 10mm…

      My guess, he already knew the ballistics was real close and made it an easier job. Anything to get another article out… Media

    3. Only missed one thing, Coonan 357 automatic pistol . 1911 design with 7+1 or 6+1 with a 5 or 4 ” barrel

        1. I have an AMT .45 Win. Mag. I win! (Oh wait, there was no .45 Mag. in the test, huh? )

          Seriously, I would say no matter the round you choose for either they are both very good. I don’t own a 10mm but my buddy had one and I have a Colt Python. The better overall gun, in my opinion, would be the 10mm purely because it’s an automatic. My Python is a joy to shoot but magazine reloading is sure nice.

      1. The Coonan is going for a fat ass $1700 to $2800 on the secondary market. It simply is not practical to compare it to a run of the mill Glock or Smith.

    4. Have both and love both. It would be hard to pick a winner but from my experience .357 mag has the edge. In a rifle, there is no comparason at all. The 357mag can reach 2000+ fps. If i could have only one, it would be mt R8 Scadium Swat team shield leaders revolver. Revolvers just work. If a round fails to go off. just wait a few seconds and pull the trigger again.

      1. Revolver failures are not as rare as you make them out to be. I have (in my limited experience had three catastrophic failures that left the weapon unusable. Of course, they are why I would rather carry a crossbow than a Taurus handgun but failures are not rare compared to automatics and the operation of an automatic is largely contingent upon training with the limited number of failures.

    5. From my reading, the .357 hollowpoint did not effectively expand, which is why it had greater penetration. There seems to be a disconnect where people on this thread and even perhaps the author believe that this is optimal performance compared to the 10mm which did expand and performed within spec, which is to stop within 18 inches. I do not know why hollowpoints were chosen for a test where more penetration is considered the winning factor. Perhaps the XTP loads are the only ones he could find with comparable weights.

      In any case, penetration tests should be performed with flat point, hard cast bullets or comparable copper solids.

      If this is a case of which hollowpoint performed better, obviously the answer is the 10mm.

    6. Both of these calibers are great and are here to stay…..But for me the Glock 29 in 10mm is one of my favorites as a backup when bow hunting, hiking, fishing, etc. The glock 20 is great with its longer barrel and higher capacity but is getting on the bulky side for most people. And even a short barreled 357 is fairly heavy with a steel frame and probably only 6 or 7 round capacity. Any experienced shooter can handle the recoil from one of these big wide slide glocks, it is more of a push than a violent jolt like most small 357 revolvers and more rounds to boot!

      1. Agreed! I have a Python and a friend of mine had a Glock 10mm and my Python is the 6” barrel and I would say the Glock was a little nicer to shoot because, as you said, there’s more of a push. I keep my Python because of all the revolvers I’ve owned it’s my favorite but there’s really a lot to be said for an automatic when comparing similar rounds (ballistics). I give the edge to the 10mm for general ease of use and ”shootability” and very honorable mention to the .357mag revolvers for their time tested performance and reliability. For a carry gun you can’t hardly beat an automatic, in my opinion.

        I currently own a S&W Model 29-2 (.44 Mag.), Colt Python (.357 Mag.), AMT (.45 Win Mag.) and the original “Magnum” a .44 Colt Walker Dragoon. I used to own a Desert Eagle .44 Mag. and after shooting these and many other large and small caliber revolvers and automatics I think I might choose a Desert Eagle (DE) .357 Magnum for my next purchase. I really loved that .44 Mag DE but I imagine that a .357 version might make an even better overall gun. The issue there would be carrying it and the 10mm Glock has the edge there.

    7. The 357 performed better with superior penetration. The 10mm expanded created more wound volume, so more bleeding. The 357 would have passed more easily through bone and skin , with the 10mm succeeding as well, but bone will have deformed both, preventing expansion and causing excessive penetration. The 10mm is great for small squishy targets. The 357 is good for small squishy targets or relatively large, hardened predators. That said, unless you are shooting something small and squishy, a big, heavy, slow bullet is always best.

    8. Springfield is offering both 4.5 and 5.5 length 10mm with its XD platform.
      (Springfield XDM 10mm) these XDs hold 15 rounds. The cost for the 4.5 is about 560.00 and the 5.5 675.00.
      That’s a lot of bang for the buck.

      15 rounds of 10mm. NICE.

    9. People just love the power and “rep” of the 357, but can they handle the shock/ suprise the 357 mag gives their hands? I have been shooting 357 Mags since 1967. What good does it do to have a gun that will have you soaking your gun in hand in epsom salt. Go with a 357 Sig p 229 or Sig P 220.

    10. People just love the power and “rep” of the 357, but can they handle the shock/ suprise the 357 mag gives their hands? I have been shooting 357 Mags since 1967. What good does it do to have a gun that will have you soaking your gun in epsom salt? 357 Sig or 10mm Sig is the way to go. The 357 Mag can and will tear you up.

    11. Good basic article; there are, however, flaws that need to be addressed. First of all, if I had to guess, I’d wager that the 357 mag load used is designed for outdoor use and not defensive use. Is that correct? Also, is the 10mm load not a defensive load? Assuming both are true that would explain the wound profile of both loads.

      Likewise, it would be great to compare the rounds in longer barrel lengths. I forget who made it but someone made a 10mm carbine (16 in barrel). When you compare the velocity gains there with the 10mm to 357 mag carbines, the 357 blows the 10mm out of the water. 357 mag rounds seem to vastly benefit from longer barrel lengths. At 6 inches and longer, no auto round can truly compare (any dispute?). I’d love to see a similar comparison with 6 inch barrels anyways…

      Ballistics by the inch has good charts for the barrel length comparison at muzzle velocity.

      Both rounds suffer from underpowered rounds but both have a number of amped up rounds too. Maybe a comparison with Buffalo Bore ammo in a 6 in platform with each round being for similar applications? Any takers?

    12. Funny, selling my 10mm this Friday, gonna miss it, but love my S&W TRR8 much more, only because of my style of hunting and reloading. While hunting, I’m more prone to take a rabbit or coyote than a black bear (I live in FL). So I have loads for 357 that are as weak as a single 000 buck moving about 700 fps and no louder than a primer, to 38 spl for not tearing up fur on a smaller coyote to a heavy 357 for deer/pig, shot capsules for snake, etc. Distance shooting with a revolver is easier, too. With a 12 gauge and 357 on your side, anything is game. From bird to deer and pigs, from meat getting to fur collecting.

      My 10mm (any auto for that matter) cant do any of this, and I got tired of chasing brass in the next county, lol. And as for reloads, moonclips make reloading a breeze. If you practice!!! Granted, still not as fast as a magazine, but not too much slower either, imho. Still, 10mm is pretty bada$$ too, if your just out for tougher game and walk past rabbits and such, it’s a great platform, just different flavors for different people.

    13. 1) .44 Magnum The King! 2.)10MM all the way.. 3.) .357 Mag is awesome.
      4.) .357 Sig is super hot round . reminds me of 7.62×25mm Tokarev from 1930’s.
      .45 ACP is 113 years old , enough said . My List.

    14. I am also biased towards the Coonan Mk 2, Which I consider to be the best large pistol I have ever owned, fully ported which made it excellant bowling pin gun, the down side was it sounded more like a howitzer, no one wanted to shoot on the range at the same time and in New Zealand we cannot use them off the range ie for hunting
      May be they could have bought them out in 44 AMT or 45 Mag
      I have never liked the trigger on the Glocks even the improve versions still arnt great

    15. Well I already have the 357 so I do believe I will purchase the new Springfield 1911 TRP™ 10MM – RMR®.
      After all the good Lord provided me with two hands.
      Happy Fourth of July to all.

    16. I would like to seen a comparison with the Coonan semi-auto 357. There are also 7 and 8 round 357 revolvers like S&W’s TTR8 swat revolver (used by police holding shields because of potential semi-automatics malfunctions where the action can get hung up on the shield). I wonder if the over penetration is better against larger animal bone.

    17. The short barrel does not do the 10mm justice. Next time try a longer barrel, like in a G20. The revolver has a 4″ bbl, and the cylinder, where as the auto loader barrel includes the chamber.
      Go carry that huge bulky 357 revolver with 6 rounds. I will stick with my G20, with 16 rounds in it.

      1. You can’t miss fast enough so magazine capacity is a non issue. There; I fixed it for you.

        1. I hate 1-liner homespun wisdom lol. That’s a rule that needs the context of range, level and kind of threat, and the type of ammo. Whether 2 or 4 legs, there are situations where you won’t be able to sit and line up shots. 10mm and 357 are both still small enough that they need to hit the CNS or the brain to immediately incapacitate aggressive targets human sized and larger, and at close range still require retention shooting and flash site picture shooting to dump rounds center mass (or a big bear head) until the threat is stopped. So more ammo is still going to be preferred for a defensive handgun.

          Adding the caveat that if you’re talking a grizzly charging you you only shoot until you still have time to get bear spray out because spray is more effective at breaking a charge, which gives you time to run the fuck away lol. And take more shots later if it still pursues.

          That is all in relation to defense not hunting.

      2. This comparison is a joke. the average 10mm shooter like myself shoot a glock 20 with a 4 inch barrel or 5 to 6 inch 1911’s. most 10mm shooters i know do not use weak loaded hornady ammo. We shoot Buffalo Bore or Double Tap hard cast or even sig 180 grain Hp. all three will generate over 600 FTLB muzzle energy. I also shoot 357. But when I’m bow hunting in black bear country I carry a Glock 20 and when in the mood my Glock 40 MOS 10mm 6 inch barrel. I know of no 10 mm shooter who would depend fully on a Glock 29 for woods defense. Way to short and lite to make full use of the 10 mm. So in my opinion this comparison is seriously flawed.
        I have hunted black bear with my 10mm Glock 40 MOS
        I have taken Black Bear with My 10mm Glock 40 MOS

        But I’m sure somewhere someone else has done the same with their trusty 357 mag.

    18. For a defensive weapon against two-legged predators, I’ll stick with my .45 autos. For defense against four-legged predators (up to and including those of the Grizzly persuasion), I load my 6″ .357 Mag with hot-loaded 180-gr Hornady XTPs.

    19. Carried the .357 for years as my duty weapon. My chief was old school and wouldn’t let us carry magnum loads, only .38+P’s. It was laughable, but then again he was from the Bonnie and Clyde days, still hanging on. I carried a .45ACP off duty and was regularly chastised as it was too “military” for off duty work….hahaha I have deer hunted with my .357’s, but prefer my .44 mag with 200 grain Silvertips.

    20. Good article. The author mentioned that the 10mm has gained popularity as a hunting round. It seems like the extra penetration of the .357 mag round might be desirable for larger game.

    21. My go to will remain the .357 Mag. I have both and found that jacketed hollow points are only about 80% in every pistol I’ve ever owned except, for a heavily modified 1911.

      Having the extra penatration allowed me to stop a crazy bear. Yes, two shots but the last one penatrated the skull… not a desirable situation I wish to repeat.

      Yes, I have several pistols and shoot 3 gun with two of them that have been grealty modified for competition. I also love target and squirrel shooting with a highly modified buckmark. So no, I don’t hate semi-autos for “games.” And a good gunsmith can make them work well.

      For real life scenarios, I choose to depend on my unmodified 686+ 7 shot. Note: “modified” means you can’t carry in most states. Just sayin…

      1. What, exactly, does your ‘modification’ have to do with CCW in most states, pray tell?

        1. Modified firearms are a key point EVEN in defensive shooting scenarios. Here in Kalifornia, it is the kiss of death. Modification is legally referred to as: any change to the basic function or operation of a firearm. It has been argued that even changing grips is a “modification.” As a gunsmith, I have to stay up to date with the state laws… a real challenge here!

          1. I wonder which is worse, California or Maryland (couldn’t figure out how to Communize MD.)

    22. 10mm all day long… With the Glock 20/29 platform, you can also shoot 40 s&w through it. Folks over exaggerate the recoil with the 10mm cartridge. Similar to the 45, it pushes more than snaps (with normal loads, not heavy lead cast Buffalo Boar cartridges). My G29 can even be customized to shoot 357 sig and 9mm.

      Same concept as buying a 357, which you can tame down to 38 loads. You can always go down in power, but can’t go up.

    23. At least a small part of the fairly recent spike in 10mm ammo sales can be explained right here:

      $350 or less for a 10mm carbine with a 16 inch _threaded_ barrel (.578 x 28). I don’t mind people laughing or making fun of Hi-Point’s blow back pistols for obvious reasons, but those relatively few who also mock the Hi-Point pistol caliber carbines are only hurting themselves, while lots of other less snooty folks are out having a lot of fun with them for very little money.

      Repeat the tests with a 16 inch barrel (an easily suppressed 16 inch barrel!) and that 10mm may be meeting or exceeding that 18 inches maximum penetration as well. For the time being though, I think the folks who load their own ammo are the main ones having a ball with loading up their own powerful 10mm rounds without spending a fortune. Even homemade powder coated hard cast lead bullets can be fairly impressive with the right loading data. 🙂

    24. How about throwing in a good .45ACP into the mix with a Hornady 200 grain XTP bullet?
      I already own a .357 revolver and two .45ACP pistols. I don’t seem to hace a need for a
      10mm pistol. There was a reason the FBI ended up at the .40 S&W, the agents couldn’t
      handle the 10mm in a defensive gun battle, and these are supposed to be trained shooters.

      Phil in TX

      1. When, exactly, did the FBI ever generally issue the 10mm cartridge to field agents? Hint: they never did. Nice try; no cigar. Do some research next time before you spout more bilge.

        1. The 10mm was developed by an FBI Colonal. Some of their tactical people still use it. Don’t think it ever made it to general issue though.

    25. I my self like both rounds , and would not 2nd guess either of them… I would ask what are using it for ? I was always in faver of 45acp that is until I put an RMR on my Glock 19 , as far as defense from humans I really feel you can not beat 9mm with the correct shot placement… with the RMR it’s no problem hitting head shots all day long at quite a distance. Thank you for the info ..

    26. Hmmm, why NO mention of the .357Sig round? It was invented to replicate the results of .357mag in a semi-auto, theoretically the best of both worlds. But with the advent of better loads in virtually all calibers, the advice of a previous poster regarding picking what you deem best and practicing with it is the ‘real’ winner of such ‘arguments’/

    27. I have both, shoot both, and love both. My problem with the article is he tested a fairly heavy for caliber 357 mag against a fairly light for caliber 10 mm. Of course the 357, under these circumstances, penetrated more. I would think a 125 gr 357 vs a 180 gr 10 mm would be a better test.
      Now, if I could just find one of those 10mm necked down to .40 I would really have something. 🙂

      1. I was thinking the same thing. Why did this yahoo say a 40 was a “necked down 10mm”. It’s a shortened 10mm. Not a big deal, but a pretty silly mistake I’d you’re a professional writer.

    28. A Coonan .357 full size or ‘çommander’ size against a similar Coonan 10mm would have been the ideal test in terms of auto vs auto, Or a Coonan full size against a 1911 in 10mm, both with five in barrels. That would eliminate the variable associated with a revolver. Just my .02

    29. This video was silly. Why into compare self
      Defense Ammo ? Or 180 grain 10mm which is widely available ?

    30. Someone here chastised me for saying negative things about this authors knowledge and writing skills. This article is further proof of what I was talking about. It makes my head hurt to think people write crap like this and others pay good money to print it, buy it, and pass it along. I know; I’m an old man shouting at the clouds.

        1. RAM, maybe, but with Killary lovers the real give-away is the hand-knitted vagina hats, too! 😉

      1. It makes my head hurt as well. The gibberish I read in gun publications anymore, being touted as “expert”, is always appalling. The author is incompetent at best. Then again, the editor is just as incompetent having let these technical errors slip by. When the author produces such trash and the editor allows it to go to print, well then you open the door to scathing criticism. And yes I could do a better job. A .40 S&W is a SHORTENED 10mm Norma. A .40 S&W IS NOT a “necked down” 10mm as the incompetent author so states. The ballistic co-efficent is the number that tells us how well a certain projectile, at a certain speed, cuts through the wind and really has nothing to do with penetration abilities. Sectional density is the number that is used to indicate which projectile will be the better penetrator. The reason the .357 158 grain bullet travelled so much further, in the testing medium, than the 10mm 155 grain bullet is because the SD (sectional density) is higher. The Hornady XTP .357 158gr bullet has a SD figure of .177 vs the Hornady XTP .400/10mm 155gr bullet which has a SD figure of .138. The longer bullet (higher SD) traveling at relatively the same speed, upon impact, as the shorter bullet (lower SD), will always penetrate further given the same resistance is experienced by both bullets. The SD figure for a certain bullet is ALWAYS the same. The SD is NOT dependent upon velocity whereas the BC figure is COMPLETELY dependent upon velocity and changes constantly as the bullet slows through it’s travel. And by the way, as so many have already stated, your test is bunk. You might be able to get away with this crap in your action-fiction novels, but not here Junior. Good day!

    31. Back when it seemed like every cop in America was carrying a .357 revolver, the “gold standard” was the Federal 125 grain JHP. I haven’t carried a .357 revolver in years myself but that would be my choice if I was going to do it. I certainly wouldn’t carry something as heavy as a 158 grain bullet. Recoil would be heavier, follow up shots slower, and the heavier bullet is going to excessively penetrate. As you found.

      I understand you were trying to match bullet weights for both… but I really don’t think may people carry that heavy a bullet in a .357 Magnum revolver for self defense. For hunting, sure. Not for chest shots on humans.

      1. Actually, the ‘gold standard’ was the Remington 357 Magnum 125 grain SJHP. Nice try; no cigar.

    32. Invalid test protocol.
      The clear plastic ‘gelatin” is NOT FBI protocol.
      Four layers of denim is NOT FBI protocol.

      1. Megan, you are absolutely right. I do wound ballistic workshops for a living and shoot a lot of gelatin, made, calibration verified and shot to the FBI protocol. That clear “pre-made” stuff is not protocol. besides the fact that penetration is far more a factor of bullet design and construction, than velocity. I’ll give him an “A” for effort but I’m afraid this test doesn’t prove much.

    33. I prefer the 155 MM round in a handgun. Sure, launching a 92 pound bullet with a 13 pound explosive warhead at 2,300 fps has some recoil, but then again I can appreciate the energy vs both the .357 and 10mm and it does much more damage to a ballistic gel block–should I ever be attacked by a block of ballistic gel..

      1. Buffalo Bore makes 180gr .357 hardcast with 1400 FPS velocity. I view both rounds as being too close to call and ymmv.

    34. The author writes that “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.”

      Necked down? Really? How much smaller does the author think the bullet diameter of the “necked down” .40 S&W round is than the 10mm?

    35. These tests are inherently flawed from a scientific standpoint simply because of using the same ballistic gel block for all of the bullet tests. Once damaged, the coefficient of friction changes dramatically because you are discharging a second (and third, etc.) bullet into gel already damaged by the first shot. Separate gel blocks should have been used for each measurement. You would still be able to put those blocks up against each other to see the differences. Unfortunately ballistic gel is relatively expensive.

    36. For self defense, both are overkill (self defense, not urban combat!). But for hunting medium game, I sold my S&W 6″ barrel .357, and kept mt Dan Wesson 5″ bbl 10mm. Because (1) That 10mm is more accurate than that .357, (2) I handload and can duplicate (safely) full power 10mm with 180 grain XTP’s.
      While both are overkill for deer broadside, a quartering shot or front-shot the deep penetration is useful if shooting from the front (I won’t take a shot with medium a handgun if the deer is facing directly away).

    37. Try those tests with true ‘Full Power’ 10mm like Underwood or Double Tap maybe even Winchester’s ST. Those results will surely change. You’ll find a need for those two gelatin blocks. Even Civil Liberty’s 60gr. will penetrate 4inches of wood and 10 inches of gelatin. Just saying! I know some worry about over-penetration but I over-penetration is OVER rated.
      I am biased however owned a .357 revolver but I love my BIG 10. We’ll never get divorced.: )

      1. Check out the Kentucky Ballistics test of four different Underwood loads of these two cartridges.from comparable sized guns. It looks to me that the .357 Magnum came out on top.https://www.youtube.com/watch?v=vu5NCcEm8qs

        As a practical matter it’s rather like comparing a 460 Ford and a 454 Chevy. Which one is more powerful depends more on the individual builds (what cam, heads , intake and exhaust systems are used) of the engines being compared , than the basic designs.

        I myself would not go or an all out load of either round if I wanted more power but would instead just get a .44 Magnum

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