The ProMag SMI30 is a 7-round magazine built specifically for the Smith & Wesson M&P Shield in .40 S&W, delivering a reliable spare or backup mag for your carry gun. ProMag engineered this magazine around their proprietary TECHNAPOLYMER construction paired with heat-treated blued-steel components, creating a durable mag that resists wear over extended use. If you're running a Shield .40 and want extra capacity on hand or a dependable reload magazine for the range, this is a straightforward, purpose-built option.
ProMag's anti-fatigue spring design lets you load and store the magazine fully charged for extended periods—up to six years according to the manufacturer—without compromising spring tension or reliability. That's handy if you keep a backup mag in a bag, car, or safe and don't cycle it regularly. The blued finish matches the aesthetics of most Shield setups and offers solid corrosion resistance for a duty or carry mag.
Built in Phoenix, Arizona, this magazine comes backed by ProMag's lifetime warranty, giving you confidence in the product. Whether you're adding a second mag to your Shield .40 setup or stocking spares for training, the SMI30 bridges the gap between OEM capacity and aftermarket durability at a practical price point.
| Brand | ProMag |
| Model | SMI30 |
| Capacity | 7 rounds |
| Caliber | .40 S&W |
| Firearm Compatibility | Smith & Wesson M&P Shield |
| Material | TECHNAPOLYMER with heat-treated blued-steel components |
| Finish | Blued |
| Warranty | Lifetime |
Yes. The SMI30 is designed specifically for the S&W M&P Shield chambered in .40 S&W. Verify your Shield's caliber before purchasing.
ProMag's anti-fatigue spring allows the SMI30 to remain fully loaded for up to six years without concern for spring compression or loss of tension, making it suitable for backup mags kept in storage or occasional-use locations.
The magazine holds 7 rounds of .40 S&W ammunition.
Yes. ProMag backs the SMI30 with a lifetime warranty against manufacturing defects.
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