What is the Shield Arms Glock 19/23 +5/4 Magazine Extension?
The Shield Arms +5/4 Magazine Extension is a precision-machined aluminum baseplate replacement that increases your Glock 19 or 23 magazine capacity by 5 rounds for 9mm or 4 rounds for .40 S&W. This drop-in extension transforms your compact carry pistol into a higher-capacity platform without sacrificing reliability or requiring permanent modifications to your firearm.
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Transform Your Compact Glock with Full-Size Capacity
The Shield Arms +5/4 Magazine Extension represents the perfect balance between compact carry convenience and full-size firepower. Engineered specifically for Glock 19 and 23 models, this premium magazine extension adds substantial capacity to your compact pistol while maintaining the reliable feeding and function you depend on. Whether you carry concealed daily, compete in USPSA matches, or train extensively at the range, the additional rounds provide peace of mind without compromising your pistol's handling characteristics.
Machined from aircraft-grade aluminum and finished with a hard anodized coating, each extension is built to withstand the rigors of daily carry and thousands of rounds of use. The precision manufacturing ensures perfect fitment with Glock OEM magazines across Gen 3, 4, and 5 platforms. Unlike cheap polymer extensions that can crack or fail under stress, the Shield Arms aluminum construction provides durability you can trust when it matters most. The low-profile design maintains a comfortable grip while the lightweight construction preserves your pistol's balance and pointability.
Installation is straightforward with the included tools and requires no permanent modifications to your magazines or firearm. The removable floor plate design allows for easy disassembly and maintenance, ensuring your magazines stay clean and functional. Each extension is thoroughly tested to guarantee flawless operation, backed by Shield Arms' commitment to quality and American manufacturing excellence.
Key Features
- Substantial Capacity Increase: Adds 5 rounds to 9mm magazines (15 to 20 rounds) or 4 rounds to .40 S&W magazines (13 to 17 rounds)
- Premium Aluminum Construction: CNC-machined from aircraft-grade aluminum for maximum durability and corrosion resistance
- Hard Anodized Finish: Military-spec Type III hard anodizing provides superior wear resistance and scratch protection
- Drop-In Installation: Simple assembly process with included allen wrenches requires no gunsmithing or permanent modifications
- Universal Generation Compatibility: Works flawlessly with Glock 19 and 23 Gen 3, 4, and 5 pistols using OEM magazines
- Removable Floor Plate Design: Easy disassembly for cleaning and maintenance ensures long-term reliability
- Low-Profile Design: Ergonomic shape maintains comfortable grip and concealment profile
- Lightweight Engineering: Minimal weight addition preserves pistol balance and reduces carry fatigue
Technical Specifications
| Specification |
Details |
| Compatible Models |
Glock 19 (Gen 3, 4, 5), Glock 23 (Gen 3, 4, 5) |
| Magazine Compatibility |
Glock OEM magazines |
| Capacity Increase |
+5 rounds (9mm), +4 rounds (.40 S&W) |
| Total Capacity |
20 rounds (Glock 19), 17 rounds (Glock 23) |
| Material |
Aircraft-grade aluminum (7075-T6) |
| Finish |
Type II anodized coating |
| Weight |
Lightweight design (minimal weight increase) |
| Installation Type |
Drop-in, no permanent modifications required |
| Floor Plate |
Removable for easy maintenance |
| Country of Origin |
Made in USA |
| Warranty |
Lifetime warranty |
Capacity Comparison
| Configuration |
Standard Capacity |
With Extension |
Capacity Increase |
| Glock 19 (9mm) |
15 rounds |
20 rounds |
+5 rounds (33% increase) |
| Glock 23 (.40 S&W) |
13 rounds |
17 rounds |
+4 rounds (31% increase) |
Frequently Asked Questions
Will this magazine extension work with all generations of Glock 19 and 23?
Yes, the Shield Arms +5/4 Magazine Extension is fully compatible with Glock 19 and 23 pistols in Gen 3, 4, and 5 configurations when used with Glock OEM magazines. The extension is designed to work seamlessly across all generations without requiring different versions or adapters.
Does this extension require any permanent modifications to my magazines?
No permanent modifications are required. The Shield Arms extension replaces your existing magazine floor plate and installs using the included tools. The process is completely reversible, allowing you to return your magazine to factory configuration at any time. Installation takes just minutes and requires no special skills or equipment beyond what's included.
How does the aluminum construction compare to polymer extensions?
Aluminum offers superior durability, impact resistance, and longevity compared to polymer extensions. The CNC-machined aluminum construction won't crack, warp, or degrade over time like polymer can. The hard anodized finish provides excellent wear and corrosion resistance, while the precise machining ensures perfect fitment and reliable function. Although slightly heavier than polymer, the weight difference is minimal and many users prefer the solid feel of aluminum.
Will this extension affect my pistol's reliability or feeding?
When properly installed with the correct magazine spring (factory spring works for this capacity increase), the Shield Arms extension maintains the same reliability as your factory magazine configuration. Each extension is precision-engineered to maintain proper magazine geometry and spring tension. We thoroughly test our extensions to ensure flawless feeding and function.
Can I still carry concealed with this extension installed?
Yes, the low-profile design maintains excellent concealability while adding capacity. The extension adds approximately the same length as a Glock 17 magazine, making it comparable to carrying a full-size Glock magazine in your compact pistol. Many concealed carriers prefer this configuration as it provides full-size capacity while maintaining the compact grip length for better concealment during daily carry.
Is this extension legal in states with magazine capacity restrictions?
Magazine capacity laws vary by state and jurisdiction. This extension increases capacity beyond the limits imposed in some states. It is your responsibility to know and comply with all federal, state, and local laws regarding magazine capacity in your area. Shield Arms does not ship products that would violate applicable laws to restricted jurisdictions.
What tools are needed for installation?
All necessary tools are included with your magazine extension. We provide the proper size allen wrenches needed to disassemble your magazine and install the extension. No additional tools, special equipment, or gunsmithing is required. For detailed instructions, visit our installation guides page.
Will this work with aftermarket magazines like ETS or Magpul?
This extension is designed and tested specifically for use with Glock OEM (factory) magazines. While it may physically fit some aftermarket magazines, we cannot guarantee proper function, reliability, or safety with non-OEM magazines. For best results and reliability, we strongly recommend using Glock factory magazines.
How much does the extension add to the overall magazine length?
The extension adds approximately the length needed to accommodate the additional rounds, resulting in a magazine length similar to a standard Glock 17/22 magazine. This makes your compact Glock 19 or 23 handle similarly to a full-size model while maintaining the shorter grip frame for better concealment and ergonomics.
Does the extension come with a spring upgrade or different follower?
The factory Glock magazine spring has sufficient capacity to accommodate the additional rounds when properly installed. The extension works with your existing magazine spring and follower. However, if you experience feeding issues or want to optimize performance, aftermarket extended magazine springs are available from various manufacturers.
What warranty coverage does this product have?
Every Shield Arms magazine extension is backed by our 100% lifetime warranty. If your extension ever fails due to defects in materials or workmanship, we'll replace it free of charge. We also offer our "Spring for Life" guarantee for magazine-related components, ensuring your investment is protected for as long as you own your firearm.
Can I use this extension for competition shooting?
Absolutely. Many competitive shooters use Shield Arms magazine extensions to maximize capacity in USPSA, IDPA, and other action shooting sports. The extension is legal in divisions that permit magazine extensions and high-capacity magazines. The aluminum construction provides the durability needed for frequent magazine drops and the demanding conditions of competition shooting.
Who Should Buy This Magazine Extension
- Concealed Carry Practitioners seeking maximum capacity in a compact platform without transitioning to a full-size pistol
- Competitive Shooters competing in USPSA, IDPA, or 3-Gun matches where magazine capacity provides a competitive advantage
- Law Enforcement Officers carrying Glock 19 or 23 as duty or backup weapons who need additional capacity
- Home Defense Users wanting maximum ammunition capacity in their bedside firearm
- Range Enthusiasts who prefer fewer magazine changes during extended training sessions
- Glock 19/23 Owners looking to maximize their pistol's capability without purchasing additional firearms
- Tactical Trainers who need reliable high-capacity magazines for extended shooting drills
- Quality-Conscious Shooters who prefer American-made, precision-engineered accessories over imported alternatives
Installation & Setup
Installing your Shield Arms magazine extension is straightforward and requires only a few minutes. Using the included allen wrenches, you'll remove your existing magazine floor plate, install the extension baseplate, and reassemble your magazine. The removable floor plate design allows for easy disassembly whenever you need to clean or maintain your magazines. For step-by-step instructions, photos, and helpful tips, visit our comprehensive installation guides page.
Made in USA with Lifetime Warranty
Every Shield Arms magazine extension is proudly designed, engineered, and manufactured in the United States using premium materials and advanced CNC machining processes. We back our products with a 100% lifetime warranty against defects in materials and workmanship. Additionally, magazine extensions are covered under our "Spring for Life" guarantee, which protects your investment for as long as you own your firearm. When you choose Shield Arms, you're investing in American craftsmanship and quality that lasts.
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Upgrade Your Glock Today
Transform your Glock 19 or 23 into a higher-capacity defensive tool without sacrificing the compact size that makes these pistols so popular. The Shield Arms +5/4 Magazine Extension delivers full-size firepower in your compact carry gun, backed by American manufacturing quality and lifetime warranty protection. Order yours today and experience the confidence that comes with superior capacity and proven reliability.
