By all rights, the .356 TSW should have killed the .357 SIG in childbirth. Since it could use 9x19mm magazines, the .356 TSW would have offered a much higher ammunition capacity in many models over the fatter .357 SIG, which required .40 S&W type magazines. Alas, it was not to be.
Just as the .356 TSW cartridge was about to become eligible for scoring at Major Power Factor in Limited Division, the USPSA Board of Directors pulled the rug out from underneath S&W. The previous Limited Division rules demanded that Major PF ammunition be available from a minimum of three manufacturers for a cartridge to be eligible for Major PF scoring, otherwise it would be scored at Minor PF. As written, this had prevented the .38 Super and 9x19mm from becoming eligible Limited Major PF cartridges because no company would load these hotter than SAAMI maximum pressure. However, the .356 TSW was already spec’ed for the higher pressure levels necessary. The revised rules added a minimum caliber clause (0.400″) for Limited Major PF.
Here is what USPSA President Andy Hollar wrote in the May/June 1994 issue of “Front Sight” magazine:
“The .356 TS&W pistol produced by the Smith & Wesson Performance Center has been on the market for more than a year and many more than the 1000 units have been sold. Ammunition manufacturers producing the ammunition or planning to produce it include Federal, Cor-Bon, and CP Bullets. Only Federal ammunition is “generally available” at this writing. The pistol may be used in Limited, but only at minor power. The good news is that the sample Federal ammunition easily made major (178.5 power factor at 4200 ft elevation) and as soon as two more commercial manufacturers come on line, the pistol will be completely legal at major power factor.”
At the USPSA BOD meeting of July 9, 1994, Jeff Nelson moved that .356 TSW ammunition be approved and be considered legal in Major and Minor PF for Limited Division. Following discussion, the motion failed with three in favor and five opposed. The .40 caliber threshold for Limited Major PF was formalized no later than the February 20, 1995 BOD meeting.
The timing of the rule change was terrible as S&W and its distributors had just begun promoting the Model 3566 semi-auto pistol and the .356 TSW cartridge as an eligible Limited Major PF combination.
Besides the “Pocket Rocket” Model 940 and the Model 3566 Limited, there was a really nice Open Division Model 3566 variant built in conjunction with Briley. (Briley’s head pistolsmith Claudio Salassa and the S&W Performance Center’s head pistolsmith Paul Liebenberg had worked together back when they lived in South Africa.) However, no one in the US really wanted to compete using anything other than a M1911 variant once the widebody frames became available. S&W also briefly offered a couple of Model 6906-sized pistols in .356 TSW known as the Model 3566 Compact.
The “Super 9″ commercial export model was basically an economy model of the Model 3566 Limited, eliminating the fancy stepped slide contours, two-tone finish, and magwell funnel. The Super 9’s 5” barrel had a standard 3rd Gen. muzzle profile instead of being machined straight for the spherical bushing of the Model 3566. In addition, the Super 9’s long slide had a standard Novak rear sight dovetail with an aftermarket LPA adjustable sight instead of the Model 3566’s BoMar sight. The version I encountered had three barrels: 9x19mm, 9x21mm IMI, and .356 TSW. One interesting thing I found was that the sear for the single-action Super 9 was originally meant for the double-action only models. I want to say that it used a standard hammer as well. The Model 3566 Limited, as with the other S&W single-action autos of its day, used what looked like a cropped version of the Model 52-2 hammer.