.357 SIG vs. .357 Magnum: Which Is More Powerful?

How well does the 357 SIG do with 160 or 200 grain bullets?

I’m gonna go with the…. Colt 45
Couldn’t help myself.

Yeah, but with new bullet technology......

jaguarxk120 said:

How well does the 357 SIG do with 160 or 200 grain bullets?

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Or out of a rifle. Per Ballistics by the Inch, the magnum does 300-400 fps faster with a 125 grain. More case volume.

You can stuff more powder in a 357 Mag so that does not surprise me. I have 1 of each so I got it covered.

I like reloading for the 357 SIG. Advantage would be that I can have 14 rounds in the gun ready.

My 1911 only holds 9 357sig rounds. But If I was in bear country I would want a much heavier bullet than a 124gr.

I'm confident that the .357 Magnum is the more powerful cartridge. It's also the more versatile cartridge. But....

Out of interested, who has a .357 Magnum load for a 125gr JHP that is loaded to powder or bullet manufacturer's max, and breaks 1400fps from a 4" barrel? Most use longer barrels for velocity testing, so I don't know how common such a load is.

Following Alliant's data for BE-86 and using a Speer Gold Dot 125gr, I get an average of 1408fps from my G23 with a 4" KKM barrel.

WrongHanded said:

: Following Alliant's data for BE-86 and using a Speer Gold Dot 125gr, I get an average of 1408fps from my G23 with a 4" KKM barrel.

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Pepe le pew-pew!

Look at the numbers


SAAMI MAP (Maximum Average Pressure)
357 Mag: 35,000 psi
357 Sig: 40,000 psi

Case Volume
357 Mag: ~25.6 gr H20
357 Sig: ~19.5 gr H20

So 357 Sig has a 14.2% higher working pressure but 357 Magnum has 31.3% advantage in case volume.

That case volume is hard to over come even with 357 Sig higher pressure, this becomes even more true as bullet weight goes up. With a 125 gr bullet 357 Sig might have a small advantage, once we get to 147 gr things are swinging toward 357 Mag and its hard to go heavier than that in 357 Sig but 158gr and 180gr bullets are pretty common in 357 Mag and 200gr not unheard of.

There are other advantages 357 Sig has that are not raw ballistics.

kcofohio said:

Pepe le pew-pew!

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I have another one which is probably not over pressure, but harder to know. It's a 124gr RMR FMJ-TCFP with 8.7gr of Power Pistol, going 1427fps from the same gun. 8.7gr is Hornady max for the 124gr XTP. And although Lyman 50th has the same bullet with 8.5gr max, they have the Speer bullet from my load above at 8.7gr. So unless the RMR is longer than those, it's probably riding the upper edge of SAAMI max for the cartridge.

Blue68f100 said:

My 1911 only holds 9 357sig rounds. But If I was in bear country I would want a much heavier bullet than a 124gr.

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I wholeheartedly agree. However, I did run some calculations with a couple formulas I was made aware of recently. One is for penetration, the other for wound diameter. They are only calculations, but I got interesting numbers with my .357 Sig flat point load.

Penetration came out to 42.3", and wound diameter worked out to 0.77". Take those numbers for what you will, I just thought it was interesting.

kcofohio said:

Or out of a rifle. Per Ballistics by the Inch, the magnum does 300-400 fps faster with a 125 grain. More case volume.

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.351 Winchester Self-Loading.
Yes, it will take down a brown bear.
The 1907 rifle was used in WW1 as an aircraft-mounted weapon.
Prisons across the country used them for decades in towers and yards.
Great round cursed by being way ahead of its time and an overweight, odd platform. The.35Rem survived because Remington featured it in a variety of platforms. Winchester didn’t give the .351 that chance at success.

Walkalong said:

I don’t like muzzle blast, so I sold the only .357 Sig I have ever owned soon after I bought it.

In the dark ages before I reloaded or knew much about ballistics, I bought a nice 686 .357 Mag, picked up a box of spicy 125 Gr stuff and the same thing happened. If I had only tried some 158 Gr stuff back then I would have never sold it.

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I would hate to have to fire the 357 sig without hearing protection. That round has a bark that that is deafening. I have to double my hearing protection when I fire it. And that's in open air. I had my sound meter at the indoor range one time. I was along the wall, 1, stall over was shooting a 44 mag, then 2 over from that a guy was shooting a 357 sig. My meter was registering 140dbA 12-15' away. At time was looking for a new set of hearing protection muffs. I went with the highest rated ones I could find, 33 dnr, and use plugs too. Now I use custom molded plugs and still wear muffs over them when shooting some calibers.

GeoDudeFlorida said:

.351 Winchester Self-Loading.
Yes, it will take down a brown bear.
The 1907 rifle was used in WW1 as an aircraft-mounted weapon.
Prisons across the country used them for decades in towers and yards.
Great round cursed by being way ahead of its time and an overweight, odd platform. The.35Rem survived because Remington featured it in a variety of platforms. Winchester didn’t give the .351 that chance at success.

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And recreated on steroids as the 350 Legend.

WrongHanded said:

I'm confident that the .357 Magnum is the more powerful cartridge. It's also the more versatile cartridge. But....

Out of interested, who has a .357 Magnum load for a 125gr JHP that is loaded to powder or bullet manufacturer's max, and breaks 1400fps from a 4" barrel? Most use longer barrels for velocity testing, so I don't know how common such a load is.

Following Alliant's data for BE-86 and using a Speer Gold Dot 125gr, I get an average of 1408fps from my G23 with a 4" KKM barrel.

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Lyman 50th Edition manual uses a 4" test barrel and lists six powders giving over 1400fps with 125gr XTP bullets:

• AA#5 - 1471fps
• Power Pistol - 1479fps
• Blue Dot - 1402fps
• 2400 - 1478fps
• H110 - 1506fps
• IMR 4227 - 1427fps

I reload for both and can confidently say that the 357 Magnum is more powerful round for round. The advantage the Sig has is the number of rounds available. I have the option in my MP Compact to use the 10 or 15 round magazine, whereas with a revolver, you are usually limited to 6 (OK - in some cases 8 rounds) of 357 Magnum. Sig is a great round, but the Magnum is simply more powerful.

AgPilot said:

I’m gonna go with the…. Colt 45

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45 Long Colt > Colt 45 > 357 Mag > 38 Special > 357 Sig

Mycin said:

Lyman 50th Edition manual uses a 4" test barrel and lists six powders giving over 1400fps with 125gr XTP bullets:

• AA#5 - 1471fps
• Power Pistol - 1479fps
• Blue Dot - 1402fps
• 2400 - 1478fps
• H110 - 1506fps
• IMR 4227 - 1427fps

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Yep I've seen those. I was asking about real world results though, which do sometimes differ.

Edit: I guess I should explain. I'm sure it can be done fairly easily, I just don't think it often is. I don't think most people like full power 125 grains in .357 magnum, despite the reputation. I've never used a 125 grain bullet in any .357 magnum load, because heavier bullets are available.

Really, the .357 Sig is just a faster 9mm. But it does a very good job of being exactly that.

In my opinion the best loadings for .357 sig are the 135 gr and 147 gr loads.

Hornady's factory 147 XTP load averaged about 1185 fps from the 4 inch Glock 32 I used to have.

That's a pretty versatile loading. Blast was moderate but far less than a hot 125 gr load.

Recoil was strong enough to slow follow-up shots.

I wouldn't mind another .357 auto, but not a Glock.

And now, with so many 10mm pistols available, I'd just get one of those.

Blue68f100 said:

I would hate to have to fire the 357 sig without hearing protection. That round has a bark that that is deafening. I have to double my hearing protection when I fire it. And that's in open air. I had my sound meter at the indoor range one time. I was along the wall, 1, stall over was shooting a 44 mag, then 2 over from that a guy was shooting a 357 sig. My meter was registering 140dbA 12-15' away. At time was looking for a new set of hearing protection muffs. I went with the highest rated ones I could find, 33 dnr, and use plugs too. Now I use custom molded plugs and still wear muffs over them when shooting some calibers.

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I took a Dave Spaulding vehicular defensive class once and fired my HK P2000 357Sig through the windshield from the drivers seat with Speer 125 GDHPs.

That blast was memorable.

Pistols chambered in 357 Sig have more “firepower”.
Compare a Glock 31 (15 rds) with a 357 Mag Desert Eagle (9rds)…the Glock wins hands down.

Yah spray and pray