Practical .40 S&W and 357 Sig Comparison

How does the 357 Sig compare with the .40 S&W regarding various bullet weights?

The 357 Sig conversion kit is simply a drop-in barrel replacement into a .40 S&W pistol, although, the pistol must be built strong enough to handle the effects of a 40,000 psi as opposed to the .40 S&W's 35,000 psi pressure limits. The 357 Sig and .40 S&W can easily co-exist and be used interchangeably based on application needs.

This is one reason why I consider the .40 S&W and the 357 Sig to be the same gun. There is no "versus" here. It simply depends on your needs.

The following table combines the bullet weights of the 357 Sig & the .40 S&W.

Table Facts:

a. Alliant Power Pistol powder was used for both calibers.

b. 4" barrel length was used for both calibers.

c. The table facts are based on Alliant testing. The Power Pistol velocities for the 357 Sig by Alliant are virtually identical to tests performed by myself and others.

d. Caution: Each powder charge shown in the table is a maximum value.

I found this table very interesting.

a. Notice the natural velocity decrease as you look at the lightest bullets and move down to the heaviest bullets.

b. Look at the velocity differences between the two calibers for the (124 & 135 grain) bullets and the (147 & 150 grain) bullets. If you extrapolate the velocity values of these two groups into the exact same bullet weights, then both calibers have quite similar velocities.

c. Obviously, the 357 Sig caters to the lighter bullets and the .40 S&W caters to the heavier bullets.

d. Notice the Energy values of both calibers. Once again you see a natural decrease in energy as you go from the lightest bullet to the heaviest bullet.

e. Look at the Power Factor values of both calibers. Usually, as the Power Factor increases, the felt recoil also increases. Notice that the Power Factor between the 357 Sig and the .40 S&W are similar. The USPSA Rule Book, 14th Edition (United States Practical Shooting Association branch of the international organization, IPSC) lowered the Major Power Factor from 175 to 165. This makes the pistols easier to control and lowers the cartridge pressures, in general.

I do have a pet peeve with IPSC rules: Even though the 357 Sig is an excellent duty round just like the .40, the 357 Sig is forced to shoot Minor Power. Reason: there is the obsolete arbitrary rule that Major Power must have at least a 10mm size bullet. The new Production Class takes care of this problem a little bit. But because of that stupid rule, 357 Sig will not be popular in IPSC. IDPA is a lot more practical in this regard!

Question: How does the blast of a full power 124 grain 357 Sig round compare to a full power 135 grain .40 S&W round? To me, both of these supersonic pistol rounds are similar, although currently, the 357 Sig has superior penetration and accuracy capabilities in general.

Question: Can you get the .40 S&W to emulate 357 Sig accuracy and ballistic efficiency using the 124/125 grain bullets? Probably not. If anyone does, please let me know. The lightest duty round for the .40 S&W is 135 grains.

Question: Can you get the 135 grain .40 S&W bullet to emulate the full power accuracy of the 357 Sig? Probably not, but sometimes it can get close. If anyone does, please let me know. The mellow 135 grain PDA .40 S&W round appears to penetrate very well, although I have not tested its accuracy against the 357 Sig. Feasibly, a bonded 135 grain .40 S&W bullet could be designed to match the penetration qualities of the 357 Sig, although, matching 357 Sig accuracy is a question mark.

Question: Can you get the 357 Sig to emulate the .40 S&W using 155, 165, and 180 grain bullets? No.

Question: Can you get the 357 Sig to emulate the .40 S&W using 135 & 150 grain bullets? Probably yes.

Question: Can you get the 357 Sig to emulate a 9mm Luger round using 115 grain & 124/125 grain bullets? Yes.

Question: Can you get the .40 S&W to emulate a 9mm Luger round using 115 grain & 124/125 grain bullets? Probably not. But, the Federal 135 PDA and 165 HS .40 S&W cartridges do a relatively good job of it.

Question: Do the Glock 9's and 357's have well supported chambers with better support than the other Glock calibers? Yes.

Question: Can you get the .40 S&W to emulate light 10mm loads? Yes.

I do know the .40 S&W and the 357 Sig calibers complement each other very nicely. As long as a .40 S&W pistol is built strong enough to handle a 40,000 psi cartridge (an extra 5000 psi over the .40 S&W standard) and the magazines can reliably feed 357 Sig ammo, then it is flexible enough to use either the .40 S&W or the 357 Sig, depending on the exact performance characteristics you desire. Do you want big? Do you want small? Do you want fast? Do you want slow? Do you want high energy? Do you want more momentum? Do you want excellent practical accuracy? Do you want excellent bullseye accuracy? Do you want a practical bullet range of 60 to 180 grains? Do you want the flexibility of light to full power loads with each caliber? Folks, this is flexibility.

I’d like to discuss some excellent information from the www.ammolab.com forum group. This ammolab site specializes in testing ammo and is one of the top 9 firearms sites on the planet:

He has tested several thousand rounds of the usual 9, 40, 45, etc. When he tested the 357 Sig Winchester Ranger and Remington Golden Saber ammo, it did something only the 10mm Silvertip has been able to do. Both of these rounds cracked the top plate that holds the gelatin blocks in place during testing. It’s obvious that these 357 Sig rounds dump more energy into 12 – 14 inches of gelatin than most other rounds he has tested.

When he reinforced the top plates, the same two 357 Sig rounds mentioned above then cracked the lower plate. The best 9mm loads, such as the Ranger 127gr +P+ barely created a ripple in the gelatin in comparison.

[A 357 Sig carbine with a 16” barrel does not push a bullet near the dubious and partially out of date magical 2200 fps for energy to supposedly make a difference. Although at 1600 to 1700 fps, the 357 Sig round is absolutely devastating and I will not describe the effects here. At 1325 – 1450, the 357 Sig is downright impressive with duty pistols.  It’s important to not only look at what the bullet did to the gelatin media (penetration, bullet expansion), but what the bullet does during actual impact as well. Both sides of the coin are important and one side will not disappear even though it’s ignored. This is not a vague plea since the bullet impact affect on gelatin can be seen, photographed, and measured.]

As we know, the United States Secret Service, the Department of Public Safety, and the Delaware State Police, to name a few, use the 357 SIG caliber, and the gentleman I’m paraphrasing has contact with a member of the shooting investigation teams of these three agencies.

His contact, an officer, stated that the Texas DPS troopers love the .357 Sig because it has produced the highest fatality rate of violent criminals, much better than anything else they have ever been issued ( including the .45). The 357 Sig has operated at 100% for every single shooting so far.

According to the annual shooting review board files, the 357 Sig is working at 99% for the Delaware State Police, which uses .357 Sig Speer GD ammo.

He also had an opportunity to review the USSS shooting files. They use the Ranger 125 grain load and report it’s the most effective pistol cartridge the USSS has ever been issued. The USSS has had four failures, all with Speer practice ammo. They are now using Winchester clean fire practice ammo.

From testing several thousand rounds of handgun ammunition, he believes that the statement, “Energy Transfer with handguns is a myth”, is only partially accurate. A few handgun rounds such as the 357 SIG caliber, actually transfer noticeable energy to the test medium, which can be seen, photographed, and measured by the distance gelatin blocks are moved, using an equal size and weight of gelatin block for each test. [These facts are observable and verifiable. The long skinny 9mm bullet using the “357 Sig engine” does indeed cause damage that the results of recovered bullets from gelatin cannot completely explain. Some of the more savvy agencies using the 357 Sig cartridge understand this.]

He stated that the .357 Sig is very close to becoming one of the finest auto pistol cartridges ever made.  It works consistently over and over again. Police agencies from coast to coast are switching to it in droves because it truly offers everything that the 9mm +P+ had going for it, plus the penetration of the 147gr 9mm along with the capabilities that the disappointing .40 S&W "wonder cartridge" was supposed to have. In a medium frame/medium sized service pistol it offers everything that the .45acp can in terms of penetration and "stopping power" but it does it in a smaller package.

[Let’s look at a .40 and 357 Sig loading of somewhat equivalent ft-lbs of energy

"Federal .357 Sig JHP 125 grains - 1,352 fps velocity, 507 ft-lbs. energy, 169 power factor (momentum)
Winchester .40 S&W Silvertip 155 grains - 1,205 fps velocity, 500 ft-lbs. energy, 187 power factor (momentum)"

Well, if you look at the power factor of the two above loads in 357sig and .40, the .40 round is much harsher to shoot than the 357 Sig round, assuming the .40 and .357sig rounds are launching from pistols of similar size and weight.]

Summary

[Using a stronger jig to hold larger amounts of gelatin in place, as some do, can hide pertinent data. The purpose of bullet testing is to see the impact of the bullet in the medium as it happens, as well as view the end results of penetration and bullet expansion. Unlike clamped down gelatin in a lab, the body is not constrained by super strong immovable plates. So designing a jig and gelatin mix which is too strong and too large provides only partial data results and may hide other important facts.]

The 10mm is an excellent all-around auto pistol caliber, from plinking to self defense to hunting. Yet, the smaller and easier to shoot 357 Sig still offers penetration advantages for skilled law enforcement officers similar to the best 10mm ammo. And the 357sig has an excellent balance of size and ease of use for non experts as well.

Both the 10 and 357sig (at least in some loadings) produce excellent shock value (rapid energy transfer into the first 3” – 6” of gelatin), which caused the above mentioned plates to break.

Winchester spent well over a million dollars developing the 357 Sig RA357T design. Is the 357 Sig a wildcat cartridge? I think not. This ammo provides the excellent penetration of the Ranger T, but relatively shallow penetration of the previous USSS issue 9mm 115 gr. +P+ loads. Essentially, the bullet expands very consistently and does not over penetrate. And what makes this bullet stand out is the ability to send a major shock value (rapid energy transfer) into the first 3” – 6” of gelatin, resulting in a severe “pressure spike punch” that exceeded the load capacity of the 1” plywood plates, causing them to break. The 10mm round in question did the exact same thing.

[Agencies that have been using this round for years like it, even after firing millions of rounds. The newer agencies give it high marks. I’ve received emails from law enforcement officers attesting to the satisfaction of using the 357 SIG, along with some of the best shooting they’ve ever done with an auto pistol caliber. I’ve seen the effects of what the 357 SIG does at a practical pistol range. When it’s loaded with low recoil ammo in the 1120 fps range, an amateur can shoot just as fast and accurately as anyone else; yet, the loud boom (low supersonic range) has an interesting psychological effect on the crowd that screams, “Be afraid even if I miss”. Lower velocities below 1000 fps with a 147 grain bullet can of course cut down on blast if so desired. The 357 Sig has been known to gouge metal pepper poppers. The special bottlenecked funnel effect of pushing the 9mm bullet down range can develop a major quick transfer into the first 3 – 6” of media to create a major “pressure spike punch” into the target. The street stats of agencies and my own observation at the range show that the 357 SIG doesn’t care what detractors say. It just works really well. In fact, all the duty calibers do well with one or more excellent loads that are available.]

The ammolab has stated in their forum that the best loads in 9mm, 40 S&W, .357 Sig, .38 Super, 9x23mm, .357 Magnum and .45acp loadings, all perform well. Here’s a list of some preferred loads:

124gr +P 9mm
127gr +P+ 9mm
147gr 9mm
125gr 357 Sig
115 & 125gr .38 Super
125gr 9x23mm
110, 125, & 140gr .357 Magnum
135gr jhp +p & 155gr, 40S&W
165gr jhp .45acp
135gr 10mm jhp +p

(Each of the above loads creates virtually identical temporary and permanent wound cavities.)

I’ll end with just one more paraphrase from the ammolab to confound you:

The 357 SIG is fun to shoot and actually offers advantages over both the .40 and 9mm that neither can match independently.

End of ammolab.com Section