ProMag SMI31 9-Round Magazine for S&W M&P Shield (.40 S&W)

The ProMag SMI31 is a 9-round replacement magazine designed for the Smith & Wesson M&P Shield in .40 S&W. It uses a heat-treated blued-steel body combined with an injection-molded follower and an anti-fatigue spring for extended readiness. This detachable magazine is intended for spare or replacement use for range work, training, or carry rotation. ProMag states these magazines are made in the USA and are backed by a lifetime guarantee against manufacturer defects.

Key Specifications

• The magazine holds 9 rounds.
• The caliber is .40 S&W.
• The body is constructed from heat-treated blued steel.
• The finish is blued.
• Designed to fit the Smith & Wesson M&P Shield pistol.
• The follower is injection-molded.
• The spring system is an anti-fatigue spring for extended service life.
• The listed dimensions are 1.20 x 6.10 x 2.35 inches.
• Package contains 1 magazine.
• Manufactured in the USA.

Durable and straightforward, the SMI31 provides a practical spare or replacement magazine for owners of the S&W M&P Shield in .40 S&W. Its steel construction and service-focused features make it suitable for regular range use, training sessions, or adding redundancy to a carry rotation. For users who prioritize simple, reliable magazine options, this ProMag offering supplies a functional, made-in-USA choice that integrates with Shield platforms.