A couple of points.
1. In defensive calibers, one has to ask about the environment in which the bullet will be used. The 357 SIG is a very good performer, but it's not the be-all and end-all of personal defence. It's probably a better penetrator (with the right bullet) than any of the others - that's one reason why "bonded" bullets are very popular in that caliber. Federal, Remington and Speer have all introduced "bonded" bullets, primarily because they hold together so well for better penetration. The initial impetus behind these bullets was LE use, where a BG's use of cover might require more penetration from their service weapons. Federal LE tests I've seen indicate that using "bonded" bullets, the 357 SIG out-penetrated all other common handgun calibers in auto glass and sheet metal. This is a definite plus for the round. However, this is specifically a law enforcement situation. For us ordinary folks, this sort of penetration is not a job requirement...
2. In terms of stopping performance on a bad guy, the standard against which all other rounds have been measured, for a decade or two, has been the .357 Magnum 125gr. JHP, running at approximately 1,400 fps or more out of a 4" barrel. Its street record is phenomenal. However, bear in mind that this street record was achieved initially in the days before reliably-expanding hollowpoints were generally available. Even with the less-than-optimum hollowpoints of the late 1970's and 1980's, there was enough velocity behind the bullet to give an excellent chance of expansion. Rounds moving slower, with the same design of hollowpoint, had an "iffy" expansion record, and over-penetration was frequent. Today, with really good hollowpoint designs, and the "next generation" bullets such as Cor-Bon's Pow'rBall and Federal's EFMJ making their appearance, bullet expansion is much more reliable, even at lower velocities. Thus, a 9mm. +P at about 1,200 fps is virtually guaranteed to expand (unless the hollow point gets clogged up with something). The 357 SIG fires essentially the same bullet at 150-200 fps greater velocity. It doesn't produce greater bullet performance.
3. A lot of folks talk about the "velocity gives greater energy dump" theory. This is unquestionably true - but just how much energy are we talking about here? No common defensive handgun round produces much more than 500-600 fpe. A typical carbine (.223, or a lever-action .30-30, or an AK-47 or SKS) or a 12ga. shotgun will triple or quadruple that energy level without raising a sweat. Quite simply, there is no existing defensive handgun round that comes close to rifle energy levels - even including RCBS and some of the other exotics - and that means that we're going to need more handgun rounds to do the job than we are rifle or shotgun rounds. As far as I'm concerned, if I have a handgun round that produces anywhere between 400 and 500 fpe, is a reliable expander for transfer of energy, and is accurate and readily controllable in rapid fire, I really don't care what caliber or cartridge is involved - it's up to me to place it where it'll do the most good (or harm, depending on one's perspective!
).
4. In the light of personal combat experience (18 years in a civil unrest situation), I've never trusted the 9mm./.38 Special class of cartridge as being a reliable fight stopper. This was on the basis of observed performance using 1970's and 1980's level bullet technology. I freely admit to this ingrained prejudice. However, in the past five years, I've had to admit that the advent of better-designed hollow point bullets, and the introduction of +P and +P+ ammunition, has made both rounds into rather more capable performers. It's very interesting to do a comparison between top loads of the 1980's (e.g. the "FBI Load" of a 158gr. LSWHP +P in .38 Special, or the Winchester Silvertip in 9mm.) and top loads of today (e.g. the Federal 9BPLE +P in 9mm., or the Winchester 130gr. SXT +P in .38 Special). The modern loads, in the same objective laboratory tests, significantly outperform the earlier-generation loads. I therefore have to concede that these weapons are now rather more effective "stoppers" than before. The 357 SIG does not offer that much of a quantum leap over the performance of previously marginal rounds, as the latter have "caught up" the technology lag.
5. I still adhere to the "bigger is better" school, again because of rather more personal combat experience than I'd like to have! It was my experience that a larger, heavier bullet was more likely to put someone down in a hurry than a lighter, faster bullet. I agree that compared to 1970's and 1980's technology, this is no longer the case - the lighter, faster stuff is vastly improved. However, so is the slower, heavier stuff! The advances in bullet and propellant technology that have so dramatically improved the smaller rounds have done the same thing for the larger rounds. I therefore still prefer carry calibers beginning with "4", and am quite unashamed about why I do so. Sure, I'll carry a .357 Magnum with great confidence, and a .38 snub or tiny .380 auto with some reservations (usually as a backup gun, or on those rare occasions when I simply can't conceal anything more authoritative): but given my druthers, I'll have a .40 or .44 or .45 on my hip.
6. As for increased wear on the gun in the 357 SIG chambering, this seems to be true, although the evidence is so far largely anecdotal. John Farnam has spoken of this (see
here for his comments). I don't know that this is a bad thing - just another factor to take into account in your gun maintenance schedules.
Hope this helps.
