Quick Answer
What is the S15 +5 Pre-Installed Magazine? A complete, ready-to-use 20-round magazine combining the patented S15 Gen 3 15-round magazine with Shield Arms +5 aluminum extension professionally installed and tested. No assembly required - just load and shoot. Doubles the capacity of OEM Glock 43X/48 magazines while maintaining compatibility with the slim-frame platform.
Buy pre-installed and let us do the work for you! Save time and ensure perfect installation with the Shield Arms S15 +5 Pre-Installed Magazine Extension. This complete magazine solution combines the revolutionary S15 Gen 3 magazine with our precision-machined +5 aluminum extension, professionally assembled and tested by Shield Arms. Experience 20 rounds of 9mm capacity (double the OEM capacity) without any assembly, guesswork, or installation time.
Perfect for competitive shooters, serious enthusiasts, home defense, and range training, this pre-installed magazine eliminates DIY installation while ensuring professional-quality assembly and function testing. Available in multiple anodized color options to match your personal style or build theme.
What's Included
- 1x S15 Gen 3 Magazine: Patented 15-round steel magazine with flush-fit profile
- 1x +5 Magazine Extension: CNC-machined aluminum extension (pre-installed with color options available)
- 12-coil power spring: High-performance spring for reliable 20-round feeding (pre-installed)
- Professional assembly: Installed and function-tested by Shield Arms technicians
- Ready to use: No assembly, tools, or installation required
Important: Steel Mag Catch Required
Critical Requirement: You must replace your plastic OEM Glock mag catch with either Shield Arms Standard Steel Mag Catch or Premium Steel Mag Catch. The S15 magazine will not function reliably with OEM plastic mag catches or other third-party products. S15 magazines are designed to work exclusively with Shield Arms steel mag catches.
Why the steel mag catch is required:
- OEM plastic mag catch experiences rapid wear with steel magazines
- Steel-on-steel contact ensures proper engagement and retention
- Prevents reliability issues and magazine drop failures
- Essential for the 20-round extended configuration's increased weight
Mag Catch Options:
- Standard Mag Catch: Ambidextrous, low-profile design ideal for concealed carry ($12.00)
- Premium Mag Catch: Hand-specific with extended knurling and beveled edges for competition ($36.99)
Why Choose Pre-Installed?
While many shooters enjoy installing their own magazine extensions, the pre-installed option offers distinct advantages:
- Zero assembly time - ready to use immediately upon arrival
- Professional installation by Shield Arms technicians ensures optimal performance
- Pre-tested reliability - every magazine is function-tested before shipping
- Guaranteed proper spring installation - 12-coil power spring correctly seated
- Perfect for gifts - ready to use without requiring technical knowledge
- Eliminates installation errors - no risk of improper assembly or component damage
- Multiple color options - choose your preferred anodized finish
- Save time - get to the range or competition faster
S15 Magazine Features
The included S15 Gen 3 magazine is the foundation of this high-capacity system:
- 15-round base capacity: 50% more than OEM 10-round magazines in same length
- Patented staggered-round geometry: Revolutionary design maximizes capacity efficiency
- Premium steel construction: Heat-treated for durability and long service life
- QPQ Nitrocarburized finish: Black coating resists corrosion and wear
- Gen 3 improvements: Enhanced manufacturing, US-based production, raised positioning ribs
- Flush-fit profile: Same length as OEM magazine for concealability
- Impact-resistant base pad: Easy-remove design for maintenance
- Made in USA
+5 Magazine Extension Features
The professionally installed extension transforms the S15 into a 20-round powerhouse:
- Adds 5 rounds: Increases total capacity to 20 rounds (100% increase over OEM)
- CNC-machined from 6061 aluminum billet for lightweight strength
- Type-2 anodized finish in multiple color options*
- 12-coil power spring included: Ensures reliable feeding at full 20-round capacity
- Unique easy-access floor plate: Service or clean without complete extension removal
- Index cuts on extension body: Improved grip when drawing from magazine pouch
- Lightweight but sturdy: Aluminum construction maintains pistol balance
- Magwell compatible: Works with Shield Arms Carry or Premium Magwells
- Fits most aftermarket flared magwells
- S15 exclusive: Compatible with Shield Arms S15 magazines only
- Made in USA
*Color Options Available: Black, FDE (Flat Dark Earth), OD Green, Gray, Red, Blue, Purple, Gold, Mud**, and more
**Note: In 2025, the anodized shade of 'Mud' slightly changed. Items previously purchased in this color may not be an exact match to the new shade.
Spring for Life Guarantee
Every S15 pre-installed magazine is backed by our exclusive "Spring for Life" guarantee. Magazine springs are wear items that can lose tension over time with heavy use. Our Spring for Life program ensures your magazine maintains peak performance throughout its entire service life. Simply contact us when you need a replacement spring, and we'll send you a new one at no charge - for life.
Technical Specifications
| Total Capacity |
20+1 rounds (9mm) |
| Base Magazine |
S15 Gen 3 (15 rounds) |
| Extension Capacity |
+5 rounds |
| Compatible Models |
Glock 43X, Glock 48 (all generations) |
| Magazine Material |
Heat-treated steel |
| Magazine Finish |
QPQ Nitrocarburized (black) |
| Extension Material |
6061 Aluminum billet (CNC-machined) |
| Extension Finish |
Type-2 anodized (multiple colors available) |
| Spring |
12-coil power spring (pre-installed) |
| Base Magazine Length |
Same as OEM Glock 43X/48 magazines |
| Extended Length |
Approximately 1 inch longer than flush-fit S15 |
| Floor Plate Access |
Easy-access design without full removal |
| Magwell Compatibility |
Shield Arms Carry/Premium, most aftermarket magwells |
| Required Accessory |
Shield Arms Steel Mag Catch (Standard or Premium) |
| Assembly Status |
Pre-installed, tested, ready to use |
| Warranty |
Lifetime + Spring for Life |
| Made In |
USA |
Capacity Comparison
| Magazine Configuration |
Capacity |
vs. OEM (10rd) |
Best Use |
| Glock 43X/48 OEM |
10 rounds |
Baseline |
Concealed carry |
| S15 Gen 3 Flush-Fit |
15 rounds |
+5 rounds (50%) |
Concealed carry, EDC |
| S15 +5 Pre-Installed |
20 rounds |
+10 rounds (100%) |
Competition, range, home defense |
Professional Applications
- USPSA Carry Optics: 20-round capacity provides strategic advantages in stage planning
- IDPA Competition: Where division rules permit extended magazines
- 3-Gun Competition: Maximum capacity from slim-frame Glock platform
- Range Training: Extended capacity reduces reload frequency for efficient practice
- Home Defense: Double the OEM capacity provides maximum ammunition availability
- Competition Practice: Match-ready magazines for training sessions
- PCC Pistol Caliber Carbines: Compatible with Glock 43X/48-pattern carbines
Color Options Guide
Personalize your build with multiple Type-2 anodized finish options:
- Black: Classic tactical look, matches most firearms
- FDE (Flat Dark Earth): Popular desert tan shade
- OD Green: Military olive drab green
- Gray: Modern gunmetal gray aesthetic
- Red: Bold accent color for competition builds
- Blue: Distinctive competition or custom build color
- Purple: Unique accent for personalized builds
- Gold: Premium metallic finish for custom pistols
- Mud: Earth-tone blend (2025 updated shade)**
Note: Color rendering may vary slightly between monitors. Type-2 anodizing provides durable, wear-resistant finish across all colors.
Maintenance & Care
The S15 +5 pre-installed magazine features an innovative easy-access floor plate design:
- Access Without Removal: Service spring and follower without complete extension disassembly
- Cleaning: Wipe magazine body exterior, clean feed lips and interior as needed
- Inspection: Check 12-coil spring for wear, follower for damage, feed lips for deformation
- Lubrication: Apply minimal lubrication to spring and follower (avoid over-lubing)
- Full Disassembly: If needed, remove extension for complete cleaning access
- Function Test: Verify proper feeding with dummy rounds before live fire
Maintenance Tip: If you notice reduced spring tension after heavy use, contact Shield Arms for a free replacement spring under our Spring for Life guarantee.
Frequently Asked Questions
Do I need to buy anything else to use this magazine?
Yes - you must install a Shield Arms steel mag catch (Standard or Premium) in your Glock 43X/48. The OEM plastic mag catch will not function reliably with S15 magazines. The mag catch is sold separately. Consider purchasing the S15 Starter Kit which includes 1 magazine + mag catch, or add a mag catch to your order.
Can I buy just the extension and install it myself on my existing S15 magazine?
Yes! If you already have S15 Gen 3 magazines, you can purchase the +5 extension separately for DIY installation. The pre-installed option is for customers who want immediate use without assembly or prefer guaranteed professional installation.
Can I use this for concealed carry?
While functional, the extended length makes this less ideal for appendix or IWB carry compared to flush-fit S15 magazines. It's best suited for competition, open carry in a magazine pouch, range training, or home defense. For concealed carry, consider the standard 15-round flush-fit S15 magazine.
How reliable is the 20-round capacity?
Extremely reliable when properly assembled. Each pre-installed magazine is assembled with the matched 12-coil power spring designed specifically for 20-round capacity, then function-tested before shipping. The S15 +5 configuration is proven in competition and trusted by serious shooters nationwide.
What colors are available?
The +5 extension is available in multiple Type-2 anodized colors including Black, FDE, OD Green, Gray, Red, Blue, Purple, Gold, and Mud. Select your preferred color when ordering. Note that the S15 magazine body is black QPQ finish; only the extension is colored.
Is the 20-round capacity legal for competition?
It depends on the division. USPSA Carry Optics allows this capacity. IDPA has division-specific capacity limits. 3-Gun typically allows extended capacity. Always verify current rules for your specific competition and division. Also check your state and local magazine capacity laws.
Will this work with my Shield Arms magwell?
Yes! The S15 +5 is fully compatible with both Shield Arms Carry Magwell and Premium Magwell. It also fits most aftermarket flared magwells designed for Glock 43X/48.
Can I remove the extension later if I want a flush-fit magazine?
Yes, the extension can be removed to convert back to a 15-round flush-fit S15 magazine. However, you'll need to replace the 12-coil power spring with the standard spring. Most users prefer buying separate magazines for different applications rather than frequently swapping configurations.
How much does the extension add to the magazine length?
The +5 extension adds approximately 1 inch to the overall magazine length. This maintains reasonable proportions on the Glock 43X/48 frame while doubling the OEM magazine capacity.
Is this magazine legal in my state?
Magazine capacity restrictions vary by state and locality. The 20-round capacity exceeds limits in several states and jurisdictions. Please check your local and state laws before purchasing. Shield Arms cannot ship to restricted locations.
What is the Spring for Life guarantee?
Shield Arms provides free replacement magazine springs for life at no charge. If your spring loses tension from heavy use, contact us and we'll send a replacement at no cost. This ensures your magazine maintains peak performance forever. Learn more about Spring for Life.
Who Should Buy the S15 +5 Pre-Installed Magazine?
- Competitive shooters needing match-ready 20-round magazines without assembly time
- First-time S15 buyers who prefer professional installation over DIY
- Gift buyers looking for ready-to-use presents for Glock 43X/48 owners
- Home defense users wanting maximum capacity in compact platform
- Range enthusiasts seeking extended capacity to reduce reload frequency
- Busy professionals who value convenience and guaranteed performance
- Anyone wanting peace of mind from professional assembly and function testing
- Color customization fans wanting to personalize their magazine setup
Pre-Installed vs. DIY Extension Kit
| Feature |
S15 +5 Pre-Installed |
DIY Extension Kit |
| Ready to Use |
✓ Immediate use upon arrival |
Requires installation (5-10 min) |
| Professional Assembly |
✓ Shield Arms technicians |
User installation |
| Pre-Tested |
✓ Function tested before shipping |
User testing required |
| S15 Magazine Included |
✓ S15 Gen 3 15-round magazine |
Must purchase separately |
| 12-Coil Spring |
✓ Pre-installed correctly |
✓ Included, user installs |
| Color Options |
✓ Multiple anodized colors |
✓ Multiple anodized colors |
| Assembly Required |
None |
✓ Yes (simple process) |
| Cost |
Higher (includes magazine + labor) |
✓ Lower (extension only) |
| Best For |
Convenience, gifts, guaranteed assembly |
DIY enthusiasts, existing S15 magazines |
Complete Your Setup
Maximize your S15 +5 pre-installed magazine performance with these complementary products:
Why Choose Shield Arms?
Shield Arms revolutionized the Glock 43X/48 platform with the patented S15 magazine system, providing 50% more capacity in the same flush-fit profile. The S15 +5 extension pushes capacity to 20 rounds - double the OEM capacity - while maintaining the compact dimensions that make these pistols ideal for concealed carry and competition.
Each pre-installed magazine is assembled by skilled Shield Arms technicians and thoroughly function-tested to ensure flawless operation. Backed by our 100% lifetime warranty against manufacturing defects and exclusive Spring for Life guarantee, and proudly Made in the USA, Shield Arms continues to set the standard for innovation and reliability.
Order your S15 +5 pre-installed magazine today - professional assembly, maximum capacity, proven reliability, ready to use.
