Smith & Wesson Sigma

The Sigma is Smith & Wesson's venture into using synthetic materials in gun construction, using high-strength polymer material for the frame. The gun is similar to a Glock safe-action pistol in both its design and operation, leading to some controversy and speculation as to the legality of the gun's patents.

Description
Created in 1994, it also incorporates a self-cocking, or Striker Fired, which is close, but not the same as double action only firing mechanism, so that the pistol can be fired without delay or preparation. The basic model is chambered for the .40 S&W cartridge, but it is also available in 9 x 19mm Parabellum and a sub-compact model in .380 ACP was also manufactured. A limited number of these guns were also chambered for the .357 SIG cartridge.

Legality
The Sigma series pistols are so similar to the competing Glock pistols that Glock sued Smith & Wesson for patent infringement. The case was settled out of court in 1997, with S&W agreeing to make alterations to the Sigma design and pay an undisclosed amount to Glock.

History and Design Improvements
In 1994 S&W rolled out the original Sigmas, the SW40F an SW9F chambered in 40S&W and 9mm luger respectively. Both were full sized models denoted by the F. Both had black polymer frame and a dark blued slide. Both had 'double stack' magazines with a capacity of 14 and 17 rounds respectively. The gun was designed to compete with the Glock 17. It boasted the same grip angle as the Colt 1911A1, and was priced slightly above the Glock 17.

Shortly after S&W introduced a pair of very small concealed carry style variants, the SW380M and the SW9M chambered in 380 acp and 9mm luger respectively. Both had a black polymer frame and a dark blued slide. Both had rudimentary sights. Both utilized a 'single stack' magazine and had a large thumb cut-out to make removal of the magazine easier. The SW9M had a magazine capacity of 7 rounds. The significantly smaller SW380M had a magazine capacity of 6 rounds.

The next incarnation of the Sigma were models limited to 10 rounds due to the 1994 Assault Weapons Ban. Smith and Wesson significantly dropped the price and changed the polymer frame color to light grey with matching slide. The model designation of these guns were SW40V and SW9V, with V being equated with Value. Later, V models were introduced with black polymer frame and stainless steel slides.

At this same time Smith and Wesson introduced the SW40C and SW9C. This version of Sigma retained the black polymer frame and black slide of the original SW40F and SW9F. These models had the Double Action Only trigger. This was a feature marketed heavily to police departments especially those transitioning from revolver to pistol as the trigger pull was the same for each shot. Also the trigger pull was long and heavy similar to a double action revolver which was believed to reduce the chance of inadvertently firing the gun. This model was almost exclusively marketed to police departments. Used models can be found with standard capacity magazines even though most guns produced during this period were restricted to 10 rounds. This is because police departments were exempt from the 10 round limit and after the provision had sunset, departments could legally sell both gun and standard capacity magazine on the secondary market.

In 1999 Smith and Wesson introduced the VE series. These models were billed as 'enhanced' and featured an improved grip, improved trigger, and enlarged ejection port. This model returned to the black coloration of the polymer frame mated with a stainless steel or black melonite slide. At this time Smith and Wesson retired the 4.5 inch barrel and switched all Sigmas to the 4.0 inch barrel. Sigmas from this era onward are considered '2nd generation' Sigmas. Shortly after the introduction of the VE series, Smith and Wesson further improved it by adding an accessory rail but did not change the model number to reflect this update.

In 2004 Smith and Wesson introduced the SW40GVE and SW9GVE. These models had a green polymer frame.

Sometime post 1999 Smith and Wesson introduced the SW40P and SW9P. These models were identical to the SW40VE an SW9VE but added porting to the barrel and slide, the purpose of which was to vent gasses upwards to fight the muzzle flip associated with recoil.

In 2011 Smith and Wesson reworked the Sigma design, dropped the Sigma name, and introduced the pistol as the SD series. This gun was priced and marketed to sit between the traditional Sigma VE series and the Smith and Wesson M&P design.

In 1999 S&W improved the Sigma series with the main changes being shortening of the barrel and the slide by 0.5 inches (12.7 mm). Other improvements included a more ergonomic and comfortable grip and a slightly enlarged ejection port, due to the proprietary accessory rails located at the front (an inexpensive adapter can be attached to turn it into a standard picatinny mount).