When SIG and Federal teamed up in 1994 to develop the bottle-nosed powerhouse that later became the .357 SIG round, everyone that was serious about personal defense took notice. One of the first offerings in the XD line once importation switched over from HS in 2002, the SA XD 357 still lives today.
Why the 357SIG?
As you can see in this image, the 357 SIG is one of the few modern bottle-necked pistol rounds in common use in the Western world. If the lower case looks familiar to the .40SW-it should as its based upon it-just necked down to accept a smaller diameter .355 caliber bullet.
Generally, this cartridge allows a 115-147 grain bullet to top out at speeds of 1300fps or more out of a 4-inch barrel which, if you do the mass times speed thing equals energy, you come up with close to enough foot-pounds downrange to equate 357 Magnum performance-- but in a semi-auto pistol.
When compared to the .40SW it was based on, which typically puts up about 400 ft. /lbs. of energy on target, the very spicy .357 SIG runs 500-550.
It other words, its super effective and no less than a dozen state police agencies use it as well as the Secret Service.
One thing though, they do have a "healthy" muzzle flash...
When SA started importing rebranded HS-2000 series guns from Croatia in 2002, the maker only produced them in 9mm. However, by 2004 they had expanded the series to include not only the classic all-American .45ACP, but also the .40S&W and .357 SIG that were, a decade ago, very new to the tactical market.
Purpose made models will have the XD-357 rollmarked on the slide.
Even though XD pistols have evolved from the HS2000 to the original XD, XDm, XDs, and now the Mod2, Springfield's current offerings in this chambering are rather limited.
Sadly, none of the new series pistols are available in this caliber and of the company's more than 40 polymer Croatian gatts, just two are in .357SIG from the maker. Both are "old-school" XD models in the 4-inch and 5-inch Full Size variants.
Both have the standard black poly frame, melonite finishes, 12-shot flush fit mags, dual spring/full length-guide rod and steel slide and barrel. Spec wise the 4-inch model goes 7.3-inches overall and tips the scales at 30-ounces unloaded while the 5-incher picks up three ounces and (wait for it) and extra inch overall length.
A number of makers to include EFK Fire Dragon, Storm Lake and Bar Sto make a number of XD/XDm conversion barrels to fit 40S&W caliber guns to make them capable of shooting .357SIG.
They offer them in a widely varying array of lengths and with or without ports or threaded muzzies for suppressor or accessory attachment. Price on these, as you may expect run from as low as $160 to twice that depending on what goodies you select.
After market kit:
Of course shopping around for these can often bring that down a little.
In general, these are just field strip, drop in, and go using the same .40SW mags that you have been using.
And let your 357 light up the night sky.