[Team American]

Please help the sadly uninformed here...what is KB factor? :22:

My only experience with .357 Sig was at the range one day...a guy let me put a magazine through his Sig 229 (I let him try my HK USPC .40 :biggrin: ), and I thought that the recoil between the two was very similar.

 

[P95Carry]

JT - should get some useful answers as IIRC more than one member here has both options. I went the 9mm route so am out of options but if I had gone that way would find choice hard.

The .357 SIG round is very appealing in terms of what it delivers but I think on balance over penetration potential would be the issue that would swing the decision toward .40.

TA - making an assumption here but ''KB'' is often used to refer to the ''Kaboom'' factor!! Quite a few guns have suffered KB's on .40 cal. I have not (yet) heard of one for a .357 SIG round.

 

[DirksterG30]

Team American - KB stands for Kaboom, which is an event that damages a firearm related to the ammunition, or a design/manufacturing defect, among other things. (I'm not sure what the technical definition is).

While I'm not sure I agree with the conclusions on this site (he seems to be pretty anti-Glock), this is a good primer on KBs -
http://www.thegunzone.com/glock/glock-kb-faq.html

Also check out the main page (www.thegunzone.com) - he's got photos of KBs of an HK USP 45 and a Springfield Armory M-1A.

 

[JT]

Yep, KB = Kaboom. I should have spelled that out.

357 SIG can use a tighter chamber than a 40, because the bottleneck design makes reliable feeding easier. The tighter chamber means less of an unsupported area near the feed ramp. This equates to less chance of a Kaboom. You always want the most support in a chamber as possible, while still letting it reliably feed. This is especially important with high-pressure cartridges.

 

[JT]

The .357 SIG round is very appealing in terms of what it delivers but I think on balance over penetration potential would be the issue that would swing the decision toward .40.

To me this is the biggest possible negative of the 357 SIG. That's why I tend to carry the 40 more.

 

[Tom357]

A friend of mine is a ballistics scientist with the VSP forensics lab, here in Richmond. He tells me that over-penetration has not been a problem with 357 SIG in shootings he has researched (probably by Richmond PD and VSP) over the past decade, where the JHP's expanded as expected. There have been some bullets retrieved from the clothing on the far side of the body, indicating complete penetration of the body, but not enough residual energy to penetrate the clothing layers on the far side.

I have a .40 conversion barrel for my P226, but prefer 357 SIG. There may not be a lot of variety in ammo, but the 125gr 1450fps pairing in a modern 9mm JHP is difficult to beat. It seems to be a sweet spot in ballistics. 115gr, 147gr, sub-sonic and exotic loadings are available but the 125gr appears to be optimal. The round shoots flat and hard, only dropping about 3" at 100 yds and still moving at about 1050fps. It is a remarkably consistent cartridge, with an average variance of less than 20fps in the Gold Dots and RA357SIGT's. It is inherently more accurate than the .40, but for combat shooting, the practical difference is negligible. I have never had a failure to feed, failure to eject, squib or misfire in 357 SIG. I cannot say that about any other cartridge.

Internet prices for bulk 357 SIG ammo are becoming competitive with premium ammo in other calibers. It is somewhat more expensive, but I am getting +P+ performance from a SAAMI spec standard round, so you really have to compare standard 357 SIG to +P+ 9mm to get an accurate comparison for the cost-benefit of the cartridge. Reloading dies and supplies are readily available.

Flash and noise are always a point of argument with 357 SIG. A 357 SIG load is the equivalent of a 9mm +P++. If you shoot a hot 9mm next to a 357 SIG, they will sound about the same. If you shoot a hot .40 next to a 357 SIG, they will sound about the same. If you think about it, this makes sense. Rounds of similar performance sound about the same; compare a 357 SIG to a standard 9mm, and the 357 SIG will be a lot louder - that makes sense, too. Flash depends most on the cartridge. I shoot Gold Dots or Rangers, both of which use low flash, very clean burning propellants. I don't have problems with losing sight of my targets in low-light conditions, and the flash seems about the same as 9mm +P+ or .40 +P ammo, at least to me.

I chose 357 SIG for a variety of reasons after careful consideration of why and how I was going to carry. That doesn't make it the right choice for anyone else. For me, it seemed to be the best all-purpose defensive round. Some will disagree. I am confident of my choice. If 357 SIG were not available, I am equally comfortable that a premium .40 would do the job, too.

 

[JT]

Thanks for the input Tom.

I always liked shooting the 357 SIG. I seemed a little more accurate with it, than the 40. Plus it is a fun cartridge to shoot. My main worry has been over penetration. I had always heard that concern, but it’s hard to get a lot of real world evidence one way or the other, because it is not nearly as common as 9mm, 40, or 45. Then again, it should be about the same as a medium powered 357 magnum load. Maybe even less concern since the 357SIG uses more modern bullet technology, which is not always used in the 357 magnum.

I was at Wal-Mart last week end and when I went by the gun counter for a quick look, I was surprised to find some 357Sig ammo there. I’ve heard of other people finding it at Wal-Mart, but this was the first time it has been at any of the ones near me. I bought both boxes.

 

[P95Carry]

Tom - excellent resumé - I was hoping folks like you could throw in the personal experience angle - mine is way too speculative.

 

[Tom357]

...My main worry has been over penetration. I had always heard that concern, but it’s hard to get a lot of real world evidence one way or the other, because it is not nearly as common as 9mm, 40, or 45. Then again, it should be about the same as a medium powered 357 magnum load. Maybe even less concern since the 357SIG uses more modern bullet technology, which is not always used in the 357 magnum.

I was at Wal-Mart last week end and when I went by the gun counter for a quick look, I was surprised to find some 357Sig ammo there. I’ve heard of other people finding it at Wal-Mart, but this was the first time it has been at any of the ones near me. I bought both boxes.

I'm both surprised and encouraged that you found it at Wal-Mart. I haven't seen it at any Wal-Mart, here.

I, too, was worried about over-penetration, but I think the key is the advancement of bullet design since the 125gr .357 Mag was king. Modern designs like the Gold Dot and Ranger expand very reliably. If they don't, then you are going to get over-penetration, just as you would with any hot ball ammo. Over-penetration is a problem with +P+ .45 ACP that fails to expand, too. If the bullet is performing to spec, though, most premium JHP ammo is designed to penetrate the magic 12"-16". I think one reason you see less choice in 357 SIG ammo, is that the .357 performance envelope is very narrow. The 115gr bullet tends to break up. The 147gr bullet sometimes fails to expand. The 125gr seems to be just right. I think over-penetration, if it is a problem, is more likely to be a problem with the 147gr designs. I'm not aware of a single report of over-penetration from VSP or RPD since they started using the 357 SIG in the 90's, and I'm pretty sure they are shooting 125gr.

My friend at the VSP lab says it is proving to be extremely effective in the field, and that they have used this round longer (8 years, so far) than they used the 10mm (3 years) and 9mm (4 years), combined. They switched from .357 Mag 4" revolvers to semi-auto pistols in 1990.

 

[Tom357]

It also occurs to me that the KB factor mentioned with regard to the .40 probably has more to do with the pistol design than the cartridge. I'm not aware of any KB's other than fluke accidents in .40, except in cases where the chamber doesn't fully support the case. Glocks designed from the ground up for .40 or 357 SIG don't have the KB history of the designs that were adaptations of the 9mm's. If someone has proof that the .40 cartridge is KB-prone by design, I'd be very interested.

 

[P95Carry]

You are right Tom I think - KB potential is due to lack of support - not the ammo per se.

 

[ExSoldier]

Well, there are quite a few 357 Sigs in my IDPA club and everybody knows who has 'em. When they're on the line and the line goes hot, you can tell immediately! I've fired the round and while it's accurate, and has not a lot of recoil, the noise is unacceptable. I shudder to think the effect of firing from a contained space like inside a vehicle. I have, btw, fired a 45 from inside a car and not had a problem. However, I DO wonder what the 400 Cor-Bon is like. Anybody have a comparison to the 357 Sig?

 

[Bud White]

I really liked the 357 Sig when i had it i might have to get another in some platform or another.. The Sigs themselfs dont work for me

 

[JT]

You are right Tom I think - KB potential is due to lack of support - not the ammo per se.

That goes along with what I was saying about the 357 SIG. Because it is a bottleneck round, you can use a tighter chamber, and still have it feed reliably. Hence, a more fully supported chamber and less chance of KB. However, I personally have never feared KBs in my Glock 23. To some people it is a plus for the 357 over the 40, but to me it is not a big factor.

 

[Euclidean]

I resent .357 SIG because whenever I ask for .357 Magnum they hand me this instead. For that reason alone I wish it did not exist. Stop confusing the ill informed gun store clerks of the world.

And stop confusing me. Any time I see .357 I have no idea what caliber it is for sure any more.

 

[Bud White]

I resent .357 SIG because whenever I ask for .357 Magnum they hand me this instead. For that reason alone I wish it did not exist. Stop confusing the ill informed gun store clerks of the world.

And stop confusing me. Any time I see .357 I have no idea what caliber it is for sure any more.

Yes i had is problem to i made sure to get snippy with the dim bulb walmart dude and ask him Can you read does it say 357 Magnum on that box... Well no. Well give me what i wanted.


Course he 45 gap takes off itll be the same thing ive heard people complaine about it all ready

 

[JT]

I'm use to it at Wal-Mart. No matter what I ask for I have to point them to the right spot. "No, the second row...all the way over to the right...no, the next one...yes, that's it.."

 

[JT]

I, too, was worried about over-penetration, but I think the key is the advancement of bullet design since the 125gr .357 Mag was king. Modern designs like the Gold Dot and Ranger expand very reliably. If they don't, then you are going to get over-penetration, just as you would with any hot ball ammo. Over-penetration is a problem with +P+ .45 ACP that fails to expand, too. If the bullet is performing to spec, though, most premium JHP ammo is designed to penetrate the magic 12"-16". I think one reason you see less choice in 357 SIG ammo, is that the .357 performance envelope is very narrow. The 115gr bullet tends to break up. The 147gr bullet sometimes fails to expand. The 125gr seems to be just right. I think over-penetration, if it is a problem, is more likely to be a problem with the 147gr designs. I'm not aware of a single report of over-penetration from VSP or RPD since they started using the 357 SIG in the 90's, and I'm pretty sure they are shooting 125gr.

Good points. I agree the 125 gr is the only way to go. It makes the smaller selection available not an important factor.

I remember when I bought my first box of Cor-Bon 357 SIG. Very impressive seeing that "Velocity 1425fps Energy 564 ft/lbs" on the side.

 

[RSSZ]

Had an opertunity to shoot a hundred or so rounds of .357 SIG out of a 2340 several years ago. If I wasn't so completely satisfied with the .45ACP would take a close look at that for CCW. I think that the .357 SIG is an excellent round for self defense. With proper bullet design,speed means less penetration-more energy dump.(given the same caliber) That's what makes the .357 Mag such a great stopper.This is what appeals to me about the SIG.------------