10mm or 357 for long-range defense -- a study


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lawboy
May 30, 2008, 04:06 AM
Introduction
Both the 357 Magnum and the 10mm Automatic have devotees amongst the fraternity of handgun shooters and, members of each group have reasons why their particular cartridge of choice is preferable. 10mm fans insist that, with full power handloads or boutique ammunition, the auto pistol cartridge churns up more foot-pounds of energy and launches heavier bullets than the mid-bore revolver cartridge. Three-five-seven shooters tout the greater flexibility of their cartridge/gun platform, and the higher sectional density of their long, 170- 180- and 200-grain bullets. Clearly, the 357 Magnum wins the popularity contest, but 10mm shooters are out there as well.

Candidly, when the issue is stopping power or general effectiveness as defensive cartridges or hunting cartridges, the above arguments impress me as nothing more than rationalizations for personal preferences. Penetration and energy figures for the 10mm and 357 Magnum cartridges are so similar that any differences are insignificant for most practical purposes. Equally true is the fact that both cartridges are excellent choices for personal defense with bullets in the 125- to 155-grain weight range. However, in the world of defensive handguns and force-on-force situations, there is one task at which both the 10mm and 357 Magnum outperform other common defensive handgun cartridges. That task is returning fire at long range.

Long-Range Defensive Shooting
Admittedly, the vast majority of self-defense shootings and even police-action shootings take place at ranges measured in feet, not yards. The urban environments where deadly encountered most often occur dictate contact distances. Nevertheless, there are situations where shootings occur at distances greater than normal. For example, here in my home state, we have several counties blessed with gorgeous woodlands that include mountain lakes and streams, and an abundance of good fishing, hunting and camping opportunities. Unfortunately, these counties are also notorious for the huge marijuana fields that are frequently found tucked way back in the mountainous areas. It is not unheard of for unwitting hikers, campers and hunters to stumble unto these fields quite by accident. Given the size of the fields, and the natural surroundings, any resultant firefight with the custodial criminals could involve distances up to 100 yards. Other possibilities are defense of a rural residence or campsite, or recreational boaters taking fire from the shoreline. Again, these are not everyday defensive shooting scenarios, but I would wager real life experiences fitting these examples could be located without excessive research.

It is possible to reliably obtain hits on targets approximating the size of an adult human torso at ranges many shooters would find extreme for typical service and concealed carry handguns. In calibers 9mm, 40 S&W, 45ACP, 38 Special, and others, typical auto pistols and revolvers with 2- to 6-inch barrels can be used against such targets at ranges exceeding 100 yards if the shooter is skilled, the range is certain, and the trajectory of the bullet is known. Handgun metallic silhouette competition confirms that this is true. In silhouette matches, all of the above factors are present, i.e., known distance and known trajectory/sight picture. In addition, the size and shape of the target also are known to the shooter. Under these circumstances, silhouette shooters pound steel targets out to 300 yards with redundancy.

While all of the most popular defensive calibers can reach out past 100 yards, the vagaries of range, trajectory and target size inherent in defensive shooting scenarios, dictate that cartridges capable of minimizing the need for precise distance and target size information, are the most desirable for long range defense. Too, pushing bullets with enough force so that they arrive on target with sufficient energy for the required work is a must. Without question, the 357 Magnum and 10mm are the two flattest shooting, most powerful cartridges widely considered appropriate for concealed carry and duty use, and both cartridges are available chambered in weapons suited to those missions. It seemed appropriate, then, to conduct a simple comparison of the two cartridges, not to determine their relative power levels, but to compare their trajectories out to 100 yards, and get some anecdotal information about how easy or difficult it is to hit with these two powerhouses from point blank range out to 100 yards using a single sight setting.

The Guns and Ammunition
In an attempt to get some uniformity in the launch platforms, we conducted the test using two revolvers rather than the more commonly-seen 357 Magnum revolver and 10mm auto pistol. The guns used were a Dan Wesson 15-2 357 Magnum, and a Smith & Wesson 610 10mm. Both guns have barrels measuring a nominal 4 inches, and both guns have adjustable sights so they were easily adjusted for the initial zero at 25 yards.

In an attempt to maximize the long-range potential of the guns in terms of both trajectory and power, we selected bullets that were towards the upper weight limit for the calibers, but not the heaviest available. In 357 Magnum we loaded a 165-grain lead semi-wadcutter (LSWC) bullet over 13.0 grains of Hercules 2400. In 10mm we used a 180-grain lead truncated cone (LTC) bullet over 8.2 grains of IMR 800X. Cases and primers used were those on hand – WW/Magtech for the 10mm, AP/CCI for the 357 Magnum. Both loads shot to a nominal velocity of 1150fps, with the 357 Magnum shooting just a tad faster than the 10mm.

Test Protocol
Because the majority of armed encounters do occur at spitting distances, we zeroed both revolvers for Point of Aim/Point of Impact (POA/POI) at 25 yards. The front sight of the 610 is about .925 above the centerline of the bore, and the 15-2 has a front sight about .845 above center bore, so differences in point of impact were minimally influenced by the differences in the positions of the sights.

Next we fired the revolvers at 7 yards to see how much hold under or hold over was needed to hit POA with each gun. The 10mm dumped six shots into a tiny cluster about whose center was almost exactly one half inch below the POA. The 357 Magnum grouped give shots into a tight ball one half inch above POA, with the sixth shot landing about an inch high. We’ll call that last shot shooter error.

We fired the guns on the 50-yard line next, this time shooting at a round, steel swinger of 12-inch diameter. The swinger was painted black so that the lead bullet strikes would show up clearly through the spotting scope. At this distance, the 10mm deposited its bullets approximately 2 inches below POA when a center hold was used. The 357 Magnum also grouped about 2 inches below POA at 50 yards.

Finally, we moved the swinger to 100 yards. At this distance, we used a high- noon hold on the 12-inch circle as we expected a significant amount of bullet drop at this distance. The 10mm bullets struck the plate in a vertical line measuring about 8 inches, with a center five to six inches below the POA. The shot pattern had surprisingly little lateral dispersion -- not more than three inches. The 357 Magnum grouped its bullets about 6-7 inches below POA, in a more crescent shaped pattern with little vertical dispersion but more lateral variance.

Impressions and Conclusions
The most significant revelation is that it was fairly easy to hit the 12-inch plate all the way out at 100 yards. A normal, 25-yard zero and a slightly elevated sight picture pretty much guaranteed hits with either handgun as long as windage also was accurately held. The trajectory numbers cited above show pretty clearly that there is no decisive or even significant trajectory difference between the two loads tested when fired from these two revolvers. The apparent 1-inch advantage of the 10mm at 100 yards is likely the result of a slightly higher front sight and not any inherent “flatness” of the cartridge or load tested. To put all of this into perspective, we also fired a Springfield Armory Longslide (6-inch) 1911 in 45ACP at the 100-yard swinger. The 1911 is regulated to place bullets 2 inches above POA at 20 yards when launching 220-grain LSWC bullets at 900fps. To get consistent hits at 6 o’clock on the swinger, a 12 o’clock hold had to be used. This amounts to a 12- to 13-inch drop; roughly double that of the 10mm and 357 Magnum revolvers. The front sight of the 1911 is about .690 above the center of its bore.

The second observation is that both the 357 Magnum and the 10mm Automatic retain impressive energy at 100 yards. The swinger used is 3/8 of an inch thick and is made from A36 mild steel plate. It weighs about 17lbs. Hits with either gun swung the metal disc very convincingly, and the ring of the shots could be heard all the way back to the firing line, even with hearing protection in place. The 45ACP hits, while audible, were of a lower pitch and volume, and did not move the swinger nearly as much. At times, it was difficult to identify exactly where the bullets had impacted the plate after shooting the 45ACP. That was not a problem with either the 10mm or the 357 Magnum.

Is there a winner between the 10mm Automatic and 357 Magnum when it comes to long-rang defense? If this admittedly limited test is indicative of the broader truth, then no clear advantage can be claimed by either cartridge. Fortunately, that does not mean that 10mm Automatic and 357 Magnum are ill suited to the role; they are not. In capable hands, either cartridge will provide surprisingly good hit ratios and impressive power at ranges well past those commonly associated with handgun defense.

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Snapping Twig
May 30, 2008, 04:17 AM
Fun read, thanks!

BikerRN
May 30, 2008, 04:29 AM
Very good read, and very informative. Thank you for taking the time to do this and write it up.

One thing I have found, if shooting a 45 ACP, if you are sighted in for 25 Yards with 230 Grain Bullets, at 100 Yards the 185 Grain +P load is "dead on". This may be of interest to 45 ACP carriers in a rural environment.

BikerRN

DawgFvr
May 30, 2008, 03:24 PM
Anything over ten paragraphs is far too long (range) for me to read...

long range and defense is an oxymoron anyhoo...eh?

beyond 50 yards? Get thee to a Rifle.

beyond 250 yeards? Call for fire...(danger close)

MCgunner
May 30, 2008, 04:38 PM
I really don't know if there's such a thing as justifiable long range defense. I can think up some scenarios, I guess, involving hiking or otherwise being in the outdoors. Most of the time I'm in the outdoors anymore, I'm hunting and usually have a rifle, but I've done my share of day hikes toting a revolver, usually.

In the choice between 10 and .357, I would choose, first and foremost, a revolver. Otherwise, it's a toss up. I'm quite partial to and reload for the .357 magnum, so that'd naturally be what I'd carry. I don't own a 10, though I think it's a great caliber, but wouldn't think most autos would be capable of the accuracy I get out of my revolvers. For HUNTING, that is somewhat more important, I guess, than self defense, but still, I like to hit what I'm aiming at. It's just that on game, I wish to place a surgical quick kill and on a human attacker, I couldn't care less if the first round hits him in the crotch and he bleeds to death slowly and painfully as I gtf out of Dodge.:D But, generally, I carry a .357 medium frame gun afield. If I'm going to carry a 40 ounce gun, as are most N frames, I'll pack my Ruger Blackhawk in .45 Colt. I hit well with it at 100 yards at the range with a 300 grain bullet loaded to over 1100 fps at the muzzle of the 4 5/8" barrel. It's unreal accurate and has enough power to stop about anything in the lower 48, let alone a marijuana culturalist in some back woods hide out that I might stumble into. A good .44 mag mountain gun, same deal. Why choose a 10mm revolver? Oh, I guess if you're taken by the concept of moon clips, but I'm not that impressed with the need for quick reloads in such a scenario, well, at least not any quicker than I can do with speed loaders in my .357 or could do with same in the mountain gun. In fact, I think reloading the Blackhawk behind cover if I actually needed to do that would be doable. Put it this way, I ain't worried enough about it to let it rule my choice of outdoor carry. A single action revolver is very strong, very accurate, and plenty enough gun to carry against man or beast in the wild if you can shoot it well. Anyway, when I'm really out in the wild away from civilization, and that happens only when I'm out west, I worry more about survival scenarios and getting to medical help than getting in a shoot out. I haven't been out there in some years, but I expect cell phone coverage is better now days, out in west Texas and New Mexico. Up in the Gila Wilderness/NF and places like that, though, I kinda doubt it. LOL

Confederate
May 30, 2008, 04:50 PM
I have no doubts that either cartridge will do the job at long range if they connect. Still, having shot quite a few clay pidgeons at 100 yards with even a .357 snubby, I remain convinced that a revolver will have the edge in shooting at that distance. Still, man-size targets at 100 yards shouldn't be too much of a problem. Too bad the 10mm just seemed to wither on the vine.

Guillermo
May 30, 2008, 04:53 PM
Well thought out and written.

My choice is simple. As I rarely get the chance to reload the .357 is my choice.

Not only is it in the "if in ain't broke" department but also there is a plethura of factory ammo available. the same cannot be said of the outstanding 10mm. In fact, I can't imagine owning a 10mm if I didn't regularly roll my own.

lawboy
May 31, 2008, 03:43 AM
Thanks for reading and commenting. I do agree my post is mighty long! :D
As far as long range defense, of course, the scenarios presented are very remote in terms of likelihood, but hey, I had to conjure up something to justify the experiment and write up!
I carry a 357 as a daily CCW and would choose that cartridge as I shoot thousands of them each year compared to maybe a couple hundred 10mm. I do own guns for both and reload for both calibers, and the 10mm is an awesome round. But the 357 gets the nod from me.
Someone made a mighty good argument for the 45 Colt in a Blackhawk and they get no argument from me. I also own a 45 Colt Bisley and same in 44 Magnum, as well as a SBH. Any of them will keep a 10-inch steel plate jumping at 100 yards without breaking a sweat. Fun stuff!

loneviking
May 31, 2008, 05:07 AM
Fun stuff indeed and one of my favorite pastimes is shooting at 100 yards with my Colt 357. And then, I have my CCW class coming up where we qualify at 7 yards!! :what:

The muzzle blast should blow holes in the target at that range...

MCgunner
May 31, 2008, 10:47 AM
We had a 12" slip blind (it's just a round gong like piece of metal) hanging at 100 yards for a long time I liked to shoot at with my .38 snub, could ring it consistently if I concentrated real hard shooting from roll over prone. Was a lot of fun, but the range authorities in the gun club decided it needed to go. Rats, well, it was getting shot up with rifles anyway. That slip blind wasn't much of a challenge with the Blackhawks. :D

Fozzy_Bear
May 31, 2008, 03:52 PM
Well, my input is this...

If you try to make the playing field level, then the calibers appear the same. But I think you went a bit far to make the playing field level...

Specifically I noticed that you used a Dan Wesson 15-2 with a 4 inch barrel. - It caught my attention since I own a 15-2, and for those who aren't familiar; it has interchangeable barrels (swapping takes under two minutes). - I personally have a 2, a 4, and a 6 inch barrel. and I have seen 8 and 15 inch barrels for sale. My point being, that if I were actually concerned about long range defense (and I'm not arguing either way on THAT topic) then I would not be using a 4 inch barrel in ANY caliber.

If I were carrying my DW in an urban environment, I'd have the 2 inch on it; If I were hiking were they might be growing pot, I'd have the 6 inch on it. (and if I regularly hiked there, I'd buy an 8 inch barrel)

So I'm not bashing the 10mm, I just think your test eliminated the 357's greatest strength (the flexibility that you mentioned) Even without the (admittedly rare) Dan Wesson, you can get 357's with barrels that would make the results at 100 yards quite one-sided.

John C
May 31, 2008, 08:05 PM
I am frankly a little surprized that the S&W 610 shot so well out to 100 yards, compared to the Dan Wesson. S&W revolvers are known to frequently have overtorqued barrels that creates a slight constriction under the frame. This can make extreme accuracy tricky. The Dan Wesson, though, doesn't have this problem, and the interchangeable barrel system is known to lock the barrels up stiffly in the barrel sleeve, making them exceptionally accurate. I have two model 15s, actually one 15 and one 715, and they're great.


-John

Brasso
May 31, 2008, 10:42 PM
I'd be more curious as to the penetration power of say, a 180gr .357 SWC to a 180gr 10mm SWC. They are both capable of 1300 fps in most guns.

lawboy
May 31, 2008, 11:28 PM
John, good point, and I agree. My thought in doing the piece was to use "utility" guns, ie., 4-inch guns that are typically carried in belt holsters or in boats, etc. as basic safety equipment. If I was anticipating some long-range gun play I would take a rifle, but as usual, when selecting a utility piece against an unknown need, you compromise. The idea then, was to see how well a compromise handgun in these calibers would do at relatively long range. It was a given that both calibers could be set up to maximize their effectiveness. Also a given that there are better calibers and platforms for that specific task.

riverdog
June 1, 2008, 10:29 AM
Leveling the playing field is good if you want life to be fair, but another way to level the field is to simply use the most common platforms for each cartridge. A 6" revolver for the .357 Mag, and a Glock G-20 or 1911 platform for the 10MM. Those would be some meaningful results. As it is there is no clear-cut winner and that's what I'd expect from a gun rag.

A little practice at the 100 yd line with any PD caliber is always a good thing. Good hits with a .45ACP are possible with even a compact model -- BTDT. Then there's the .41 Rem Mag. . .

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