Enhance Your S&W M&P Shield .40 S&W Performance with the ProMag SMI31 9-Round Extended Magazine

For Smith & Wesson M&P Shield .40 S&W owners seeking a significant enhancement to their firearm's capacity and overall utility, the ProMag SMI31 9-round extended magazine offers an indispensable upgrade. This meticulously engineered accessory is designed to seamlessly integrate with your existing M&P Shield in .40 S&W, transforming its capabilities whether you're at the range, engaged in self-defense training, or preparing for personal protection scenarios. If you've ever wished for more rounds without needing to carry a second magazine or perform frequent reloads, the ProMag SMI31 is precisely the solution you've been looking for.

Why Opt for an Extended Magazine for Your S&W M&P Shield .40 S&W?

Many firearm owners, particularly those who rely on compact pistols for everyday carry or home defense, often face the trade-off of concealability versus ammunition capacity. The S&W M&P Shield in .40 S&W, while being a highly popular and reliable choice for its size, typically comes with standard magazines holding 6 or 7 rounds. While adequate for many situations, there are undeniable benefits to increasing your onboard ammunition supply.

An extended magazine like the ProMag SMI31 addresses this directly by providing an additional 2-3 rounds, pushing your capacity to 9 rounds in the .40 S&W caliber. This seemingly small increase translates into substantial advantages in various practical applications:

• Reduced Reloads During Training: For frequent range visitors, fewer reloads mean more time spent on target acquisition, recoil management, and improving fundamental shooting skills. This also conserves wear and tear on your magazine release and springs.
• Enhanced Self-Defense Preparedness: In a high-stress, self-defense scenario, every round counts. Having an extra two or three rounds on tap can provide critical peace of mind and potentially make a decisive difference. The ability to engage threats for a longer duration without interruption is a tactical advantage.
• Improved Grip and Handling: The extended base plate of the ProMag SMI31 magazine often provides a more complete grip for shooters with larger hands, enhancing comfort, control, and consistency, especially during rapid firing sequences. This can contribute to better accuracy and faster follow-up shots.
• Versatility in Application: Whether you're using your M&P Shield for concealed carry (where the extended grip might be less discreet but manageable for certain carry positions), home defense, or as a secondary firearm, the increased capacity provides a layer of versatility that standard magazines cannot.

Key Features and Engineering of the ProMag SMI31 Magazine

The ProMag SMI31 is not just an ordinary magazine; it's a testament to robust design and manufacturing intended for reliable performance. Crafted with attention to detail, its features are specifically tailored to meet the demands of discerning firearm enthusiasts and professionals.

Durable Construction for Consistent Performance

At the core of the ProMag SMI31's reliability is its construction. The magazine body is precision-engineered from heat-treated steel, a material renowned for its exceptional strength and resilience. This robust foundation ensures the magazine can withstand the rigors of frequent use, repeated loading and unloading, and exposure to various environmental conditions without deforming or failing. The heat-treatment process further enhances the steel's molecular structure, contributing to its long-term durability and resistance to stress cracks.

Black Oxide Finish: Protection and Discretion

Each ProMag SMI31 magazine features a sleek black oxide finish. This specialized coating serves multiple critical purposes:

• Corrosion Resistance: The black oxide treatment provides a vital layer of protection against rust and corrosion. Firearms and their accessories are often exposed to moisture, sweat, and other corrosive elements. This finish acts as a barrier, preserving the magazine's integrity and aesthetic appeal over time.
• Reduced Glare and Reflection: In tactical or low-light situations, a non-reflective finish is crucial. The matte black oxide reduces glare, helping to maintain discretion and prevent unwanted reflections that could compromise a shooter's position.
• Enhanced Aesthetics: Beyond its functional benefits, the black oxide finish gives the magazine a professional, understated appearance that complements the design of the S&W M&P Shield.

High-Performance Anti-Fatigue Spring

Inside the steel body, the ProMag SMI31 utilizes an injection-molded follower paired with a heat-treated chrome silicon wire spring. The choice of chrome silicon wire is deliberate; this material is engineered for superior fatigue resistance compared to standard spring steels. This means the spring can endure countless compression and decompression cycles—the natural function of a magazine spring—without losing its tension or elasticity. A robust spring is paramount for:

• Reliable Feeding: Consistent spring tension ensures that rounds are pushed upwards smoothly and reliably into the firearm's chamber, minimizing the risk of feed failures.
• Longevity: The anti-fatigue properties extend the operational lifespan of the magazine, providing dependable performance for years to come.

Ergonomic Polymer Extended Base Plate

The most visually distinct feature of the ProMag SMI31 is its extended base plate. This component is constructed from durable, impact-resistant black polymer. It serves several critical functions:

• Increased Capacity: The primary purpose is to accommodate the additional rounds, allowing for the 9-round capacity in .40 S&W.
• Enhanced Grip: For many shooters, especially those with larger hands, compact pistols can present a challenge for a full, comfortable grip. The extended base plate provides extra real estate for the pinky finger, completing the grip and significantly improving firearm control, especially during rapid fire. This translates to better accuracy and more confidence.
• Magazine Retention: The extension also provides a larger surface area for easier insertion and removal of the magazine, particularly beneficial during tactical reloads or when operating under stress.
• Protection: The polymer base plate offers a degree of protection to the magazine body and internal components if the magazine is dropped on a hard surface.

Compatibility and Installation

The ProMag SMI31 magazine is engineered exclusively for the Smith & Wesson M&P Shield pistol chambered in .40 S&W. It is crucial to verify your pistol's caliber to ensure proper fit and function. This magazine will not fit the S&W M&P Shield 9mm or any other firearm model. Its design is specific to the original Shield platform, ensuring optimal performance and safety.

Installing the magazine is as straightforward as inserting any standard magazine into your M&P Shield. Ensure the magazine is loaded correctly, then firmly insert it into the magazine well until you hear or feel a positive click, indicating it is properly seated and locked in place by the magazine catch. Always perform a function check by pulling the slide back to ensure it cycles properly and then safely unload the firearm.

Real-World Scenarios and User Outcomes

Consider these common scenarios where the ProMag SMI31 magazine proves its worth:

• Range Training: Imagine a typical range session. With a standard 7-round magazine, you're reloading every few seconds during a rapid-fire drill. With the ProMag SMI31, you get two more crucial shots before needing to reload. This means more continuous practice, better focus on your technique, and fewer interruptions, leading to more efficient training. Users often report a more fluid training experience.
• Home Defense Setup: For a home defense pistol, having maximum reliable capacity is paramount. The ProMag SMI31 provides this crucial advantage without compromising the Shield's inherent reliability. Should a critical situation arise, those extra rounds are immediately accessible, offering a significant psychological and practical edge. Users experience increased confidence in their preparedness.
• Tactical Drills: Practicing reloads is vital, but sometimes you want to simulate longer engagements. The ProMag SMI31 allows for extended strings of fire, enabling drills that more closely mimic real-world scenarios where multiple targets or prolonged engagements might occur. This helps refine shooting skills under various conditions.
• Comfort and Control for Larger Hands: Many shooters find the M&P Shield’s compact grip challenging. The extended base plate addresses this, allowing a full four-finger grip. This translates directly to better recoil management, a more stable shooting platform, and improved accuracy, particularly for follow-up shots. Shooters often comment on the immediate improvement in the feel and control of their firearm.

Maintaining Your ProMag SMI31 Magazine

To ensure your ProMag SMI31 magazine provides years of reliable service, a few simple maintenance practices are recommended:

• Regular Cleaning: Periodically disassemble your magazine for cleaning. Use a mild solvent and brush to remove any residue, dirt, or carbon buildup from the spring, follower, and interior of the magazine body. Ensure all parts are dry before reassembly.
• Inspect for Wear: During cleaning, visually inspect the spring for any signs of kinking or rust, and the follower for cracks or excessive wear. Check the feed lips of the magazine body for any deformation. While ProMag magazines are built to last, regular inspection helps identify potential issues before they impact performance.
• Avoid Overloading: Always load your magazine to its specified capacity (9 rounds for the .40 S&W version). Overloading can damage the spring and feed lips, leading to reliability issues.
• Proper Storage: Store your magazines in a clean, dry environment, preferably unloaded, to prevent long-term compression fatigue on the spring. While modern springs are designed to withstand being loaded for extended periods, unloading them when not in use can prolong their lifespan.

Frequently Asked Questions About Extended Magazines

Will this magazine fit my S&W M&P Shield 9mm?

No, the ProMag SMI31 is specifically designed and engineered for the Smith & Wesson M&P Shield chambered in .40 S&W. It will not fit the 9mm version of the M&P Shield or any other firearm model.

Are ProMag magazines reliable?

ProMag has a long-standing history in the firearm accessory market. Their magazines are designed and manufactured to rigorous standards, utilizing durable materials like heat-treated steel and chrome silicon springs. Many users find ProMag magazines to be a reliable and cost-effective option for increasing their firearm's capacity. As with any firearm accessory, proper maintenance and occasional testing are recommended to ensure optimal performance.

How does an extended magazine improve shooting?

An extended magazine, by providing additional rounds, reduces the frequency of reloads during training, allowing for more continuous practice and focus on shooting fundamentals. The extended base plate often provides a fuller grip, especially for shooters with larger hands, leading to better control, recoil management, and potentially improved accuracy.

Can I use this magazine for concealed carry?

While the ProMag SMI31 magazine increases capacity and grip length, the extended base plate will make your S&W M&P Shield .40 S&W less concealable than with a flush-fit magazine. Many users opt to carry the pistol with a standard flush-fit magazine for maximum concealment and use the extended magazine as a spare or for home defense. The choice depends on your personal carry preferences and body type.

What is the advantage of a black oxide finish?

The black oxide finish on the ProMag SMI31 magazine provides excellent corrosion resistance, protecting the steel body from rust and environmental degradation. It also creates a non-reflective, matte surface, which can be advantageous in various shooting conditions by reducing glare.

The ProMag Advantage: Trusted Quality

ProMag Industries has established itself as a reputable manufacturer of firearm magazines and accessories. Their commitment to using high-quality materials and precision manufacturing processes ensures that their products, like the SMI31, meet the functional demands of shooters. When you choose a ProMag magazine, you're investing in an accessory designed for durability and dependable operation, providing a valuable enhancement to your Smith & Wesson M&P Shield .40 S&W.

This specific ProMag SMI31 9-round extended magazine, along with a wide array of other high-quality firearm accessories, is readily available at DEGuns. Elevate your shooting experience and preparedness by acquiring this essential upgrade for your S&W M&P Shield .40 S&W today.

Product Specifications Overview

Feature	Detail
Model	ProMag SMI31
Firearm Fit	Smith & Wesson (S&W) M&P Shield .40 S&W only
Caliber	.40 S&W
Capacity	9 Rounds
Material	Heat-Treated Steel Magazine Body, Black Polymer Extended Base Plate
Spring Type	Heat-Treated Chrome Silicon Wire
Follower	Injection-Molded Polymer
Finish	Black Oxide
UPC	708279011740
Availability	DEGuns