This was a development by Smith & Wesson and Federal during the early 1990’s as the Team Smith & Wesson for their IPSC shooting team. During the late 80’s, shooters began migrating away from the 45 ACP to the 38 Super, as the loads were loaded hot enough to make major power factor (the weight of the bullet in grains multiplied by the velocity in feet per second, divided by 1,000). Because of the muzzle breaks that the shooters used, they could load hotter loads, something the USPSA directors had a problem with and had the idea of banning cartridges that were loaded above SAAMI specifications. Shooters then moved up to the 9×21 IMI with its 21mm case length and solved that issue as there were no standards for the 9×21. The TSW round increased the case length of the 9×21 by 0.5mm and created a load that could easily make major power factor. The USPSA however changed the rules again, firstly by stipulating that at least three manufacturers load rounds to major PF, and then increasing the minimum caliber from .354 that was standard for Limited Class to .400.
Smith & Wesson marketed their TSW exclusively for the IPSC market and afterwards had nowhere to go and no one to sell their guns to, so the TSW faded into the background even though there are some die-hard shooters still holding out.
