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The Difference between 357 Mag and 357 sig?

Discussion in 'Handguns: General Discussion' started by Columbus Archer, Mar 10, 2006.

  1. Just curious as to what the difference is between the 357 mag and sig? Is the sig closer to a 38 special strength wise?
  2. diesel_furry

    diesel_furry Well-Known Member

    The 357 mag is a 357 mag , more powerful shot from a revolver

    the 357 sig is a necks down 40 , and used in semi auto pistols

    factory the 357 mag is around 1300 fps to 1500 , and about 700+ ft lb's with bullets around 150 to 180gr give or take some

    the 357 sig is 1350 fps and 510 ft lb's with 125 gr bullet

    the mag is for hunting and the sig is for target and Self defense
  3. 3rdpig

    3rdpig Well-Known Member

    You don't consider the 357 mag a self defense round? :what:
  4. diesel_furry

    diesel_furry Well-Known Member

    the 357 mag will work for about anything you want to do with it

    being target , self defense , hunting

    just ponting out hunting to show the dif between the sig and mag
  5. MCgunner

    MCgunner Well-Known Member

    People, people, people, there's more to a cartridge than how much powder it holds. Compare SAAMI pressures. Now, 125 grain Sigs are supposed to approximate the .357 mag in an auto pistol, close I must say. However, the .40 with light bullets can do the same thing, so what's the point?????? I fail to see the need in the Sig round. Truth be told, it's more a marketing ploy by Sig Sauer than any advancement in ballistics. Agencies around the country, Texas Department of Public Safety included, were happy with the .357 mag for many years of its service and, so, naturally fell for the ploy. But, they'd be just as well armed with a .40 and the right ammo. :rolleyes: The .357 Sig is actually a .355, uses 9mm bullets, but the marketing department no doubt came up with the idea in the first place. I can hear it now, "they want .357 ballistics from an auto pistol, we'll give it to 'em!"

    Now, the .357 mag is MUCH more versatile as an outdoor round while being one of the most effective self defense calibers you can get in a revolver. You can load it with 180 grain pills to shoot some fairly heavy game and even defend yourself against black bears. But, the Sig round is limited to not much more than the 125 grain pill they designed for duty weapons. I really got no use for the Sig round. I have plenty of faith in both my 9mms and my .45 ACP for self defense in an auto pistol. For outdoor use, I would have to put my faith in mostly the magnums from .357 up except for my favorite all time magnum, the .45 colt. :D I handload my .357 heavy loads to around 750 ft lbs. My .45 colt from the 7" barrel of my contender pushes 1000 ft lbs with a 300 grain bullet, near 900 ft lbs from my 4 5/8 inch Blackhawk. A standard SAAMI load pushes about 400 ft lbs with a 255 grain pill. Same HUGE case, different working pressures.

    What makes these pills pretty close in velocity and energy, though, in the 125 grain loadings is the working pressure of the cartridges, not the volume of the case! The volume of the case is NOT that much different anyway being as the Sig round is larger in diameter, a bottle neck round. But, it's the working pressure that matters. This is why the puny little 9x19 parabellum can push 400+ ft lbs in a +P loading, pressure. It's a tiny little case, only marginally bigger than the .380 ACP, also a 9mm diameter bullet. But, the .380, chambered in blow back pocket pistols, works at MUCH lower working pressures. It is only 2mm shorter in case length. It's the pressure that is the difference.
  6. jc2

    jc2 member

    For all practical purposes, there's not enough difference between the 9x19 and 357 SIG to make of difference.

    On the other hand, the 10mm is the autoloader equivalent of the .357 Magnum. For all practical purposes, the .357 Magnum and 10mm are ballistic twins.
  7. MCgunner

    MCgunner Well-Known Member

    Basically true loaded to potential. But, there are a lot of neutered .357 mags. The "standard" in .357 mag self defense, is the 125 grain load to about 550 ft lbs. But, you and I both know that's very light in the caliber. That's the standard that was used as a target for the Sig, though. Like I say, it is a marketing ploy, nothing more really. Even USES 9mm bullets! :rolleyes: I actually PREFER the 9x19. In a service gun, in +P+ loads, it can almost equal the Sig, come within 75 ft lbs anyway, and yet it can be had in super compact autos. The Sig round is fatter and loaded in a small auto, will give up a few rounds in the magazine just like it's .40 caliber parent case. The 9X19 is a more efficient package and absolutely enough gun for self defense, well, as enough as anything I reckon.

    Anyway, I've never found a good, logical reason to shoot either .40 or .357 Sig. I would, however, see the use in the 10mm. It IS a .357 in an autoloader. Now, right there, you see why I think the Sig round is all about marketing. The 10 existed long before the Sig came out. The TDPS was looking for a "357 autoloader" and the 10 is the only common self defense caliber that equals the .357 magnum ballistically. If they'd have named the 10mm the ".357 auto magnum", it'd 've sold to the DPS. Instead, they settled on a lesser round because of the name! :rolleyes:
  8. Graystar

    Graystar Well-Known Member

    The .357SIG exist for a single purpose...to provide the same high-powered round that is found in the typical .357 Mag police service revolver in a semi-auto package. This was because the .357 Mag service revolver has a very successful history in police work. The hope was to create a handgunl that could provide the same performance but also provide more rounds.

    The .357SIG isn’t as versatile as the revolver round and generally sticks to a narrow range of power. .357 Mag rounds are available that range from less powerful than .357SIG to far more powerful. But that's okay as long as you remember what the intent of this round is.

    A Federal Premium .357SIG round produces 506 ft-lbs whereas an Federal Premium 9mm produces 353 ft-lbs. That’s over 43% more energy. That’s a big difference.
  9. jc2

    jc2 member

    The 357 SIG exist for a single purpose--to sell handguns, period. It was part of an effort by SIG to reclaim the momentun they lost in the LE market-place (largely to Glock) because they were so slow in delivering a .40 S&W weapon.
    Then it failed miserably--it falls well short of the .357 Magnum. They 357 SIG was hyped by SIG in as such but falls well short of that mark in actual practice. Basically, it is 9x19 in a short, fat case.
    Not really. It's one of those numbers that looks big, but what is actually measured is rather small. Frankly, a 153 fpe is not enough difference to make a diiference--in actual enery, it is a very small amount
  10. MCgunner

    MCgunner Well-Known Member

    Well, I carry +P 9mm stuff that puts out 400 ft lbs, so it's down 100 ft lbs to the Sig load, but that's in a very compact pistol. In a full size gun, it makes 440 ft lbs, so it's down about 60+ ft lbs. That's not that significant IMHO. Now, consider that the parent .40 S&W case makes well over 500 ft lbs in it's lighter bullet loadings of 135 to 155 grains. Why the .357 sig when you have equal exterior ballistics with a bigger, heavier bullet in the .40????? Where's the need???? It's all about marketing, plain and simple. Call it a .357 and Law Enforcement will come.
  11. 355sigfan

    355sigfan member

    A Federal Premium .357SIG round produces 506 ft-lbs whereas an Federal Premium 9mm produces 353 ft-lbs. That’s over 43% more energy. That’s a big difference

    Not quite. Lets compare the Winchester Ranger +P+ grain 9mm at 1250 fps vs the 125 grian 357 sig at 1350fps. Thats 440 footounds for the 9mm vs 500 for the sig. Hardly anything to get worked up over.

    The 40 is also not that much to get all worked up about either. It provides what, a mear .05 expansion over the 9mm with equal penetration figures. For that extra expansion you pay for with with more than 45 acp recoil. You pay a lot more for you ammo. You have guns wearing out much quicker and you have KB's. I no longer use the 40.
  12. Graystar

    Graystar Well-Known Member

    Alright then...forget Federal and lets move to CORBON. 575 ft lbs for their .357SIG. Bottom line is that the power rating for 357SIG is well above 9mm.

    It is my understanding that there are at least two significant reasons for using 357SIG over .40. The first is that the round appears to be a bit more accurate than the .40, which is not important for self-defense but important for policemen trying to take down a BG at a distance.

    The second is that the smaller round has better penetration. Again, not important for personal defense but important for police who might have to shoot a BG through a car door or window.
  13. 355sigfan

    355sigfan member

    Wrong again graystar. With Corbon the 125 grain 357 sig is rated at 1450 fps. While the 125 grain 9mm Corbon is rated at 1250 fps. Thats only a difference of 150 footpounds still not enough to get worked up over. 583 for the sig and 433 for the 9mm. Besides energy is not that numbers you should be looking. Penetration and expansion figures are far more important. In that area the 9mm and 357 sig are identical.

  14. Graystar

    Graystar Well-Known Member

    What...you're saying that the 357SIG doesn't have a higher power rating??? I think you're the one that's wrong.

    575 ft-lbs is well in the .357 Mag range of power. You're telling me that there's no difference between 9mm and .357 Mag??

    You treat 150 ft-lbs like it's nothing when in fact it is a significant percentage of the 9mm's power rating. If it wasn't significant then we wouldn't need anything more than .38 special. 150 ft-lbs is significant.
  15. 355sigfan

    355sigfan member

    Take a look at the 357 sig jhps expansion and the 9mm pics. Tell me there is a significant difference.

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  16. Graystar

    Graystar Well-Known Member

    There's no difference, as there shouldn't be. I would fully expect manufactures to insure that the bullets used are of a design and appropriate hardness to allow full expansion at the specified power rating.
  17. 355sigfan

    355sigfan member

    A 12 inch hole that is .75 caliber from a 9mm is the same as a 12 inch hole from a .75 caliber 357 sig.
  18. ROAshooter

    ROAshooter member

    357 vs 357sig?

    Such a waste......we all KNOW..the 223/5.56 is....SUPERIOR......for everything!!!!!
  19. 355sigfan

    355sigfan member

    Go away pest. Only those who have something to contribute are welcome here. Personal attacks need not apply. Grow up and act like an adult.
  20. ROAshooter

    ROAshooter member


    INSULTS.....from the mouth of babes

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