Paul, the TRYBE Defense Smith & Wesson M&P Shield Match Grade Non-Threaded Pistol Barrel will not fit properly with your California model chamber indicator. It may fit if the indicator is removed, but doing so could leave an unsightly open pocket on top of your slide.
The TRYBE Defense Smith & Wesson M&P Shield Match Grade Non-Threaded Pistol Barrel will fit your M&P9. It is a 3.1" barrel, and will fit all 9mm Shields that come with a 3.1" barrel.
The TRYBE Defense S&W M&P Shield barrel will not drop into a California-compliant gun. The loaded chamber indicator lever is squared on the end, rather than rounded. Removal of the LCI or replacement with an Apex Tactical "no profile" lever will resolve this issue and allow the TRYBE pistol barrel to function in CA firearms
The TRYBE Defense Smith & Wesson (S&W) M&P Shield Match Grade Non-Threaded Pistol Barrel is designed to fit all Shield model pistols with a 3.1" barrel chambered in 9mm.
The TRYBE Defense Smith & Wesson (S&W) M&P Shield Match Grade Non-Threaded Pistol Barrel is a drop in barrel.
The TRYBE Defense Smith & Wesson (S&W) M&P Shield Match Grade Non-Threaded Pistol Barrel will fit and function as intended in the M&P Shield 1.0, 2.0, and Shield Plus.
The accuracy of the TRYBE Defense Smith & Wesson (S&W) M&P Shield Match Grade Non-Threaded Pistol Barrel will depend on a handful of factors but primarily the shooter. So it is hard to state how accurate the TRYBE Defense Smith & Wesson (S&W) M&P Shield Match Grade Non-Threaded Pistol Barrels will be.
These are factory length, 3.1"