What is the Shield Arms SA-15 Complete Folding Lower Receiver?
The SA-15 Complete Folding Lower Receiver is a fully assembled AR-15 lower receiver with a patented built-in folding mechanism that enables compact storage and transport without the need for bulky adapters. Built from precision-machined 7075-T6 billet aluminum and featuring premium components including an SB Tactical SBA3 brace, ALG Advanced Combat Trigger, and Radian safety selector, this complete lower saves over half a pound compared to traditional folding adapter systems.
Pairs perfectly with:
Revolutionary Folding Design Without Compromises
The Shield Arms SA-15 Complete Folding Lower Receiver represents a breakthrough in AR-15 design by integrating the folding mechanism directly into the lower receiver itself. Unlike bulky folding stock adapters that add significant weight and complexity to your build, the SA-15's patented design eliminates the need for aftermarket adapters entirely. This integrated approach saves over half a pound compared to popular folding adapter solutions while maintaining full compatibility with standard AR-15 upper receivers and components.
Precision-machined from 7075-T6 aircraft-grade billet aluminum, the SA-15 lower receiver undergoes a rigorous manufacturing process that ensures dimensional accuracy and structural integrity. The lower features a matte black hard-coat anodized finish per Mil-8625 Type 3 Class 2 specifications, providing superior corrosion resistance and durability for years of reliable service. Each lower includes premium components carefully selected for performance and reliability, including an SB Tactical SBA3 adjustable pistol brace, ALG Advanced Combat Trigger, Radian ambidextrous safety selector, B5 Systems grip, and mil-spec end plate and castle nut.
Designed for shooters who demand compact transportability without sacrificing functionality, the SA-15 is ideal for vehicle storage, backpack carry, and discreet transport scenarios. The folding mechanism operates smoothly and locks securely in both open and folded positions, while the precision-machined magazine well with beveled feed lips ensures fast, reliable magazine changes in any shooting situation. Weighing just 2.5 pounds complete, the SA-15 provides an exceptional foundation for building a compact, capable AR-15 pistol or rifle.
Key Features
- Patented Built-In Folding Mechanism - Integrated design eliminates the need for bulky folding stock adapters, saving over 0.5 lbs
- Premium 7075-T6 Billet Aluminum Construction - Aircraft-grade aluminum precision-machined to exacting tolerances for maximum strength and durability
- Complete Assembly with Premium Components - Ships ready to install with SB Tactical SBA3 brace, ALG Advanced Combat Trigger, Radian ambidextrous safety, and B5 Systems grip
- Proprietary H2 Buffer System - Includes specially designed H2 weight buffer optimized for the folding lower design
- Precision Magazine Well - Beveled feed lips and tight tolerances ensure smooth, reliable magazine insertion and changes
- Enhanced Fit Adjustability - Upper tension screw behind grip allows you to eliminate any play between upper and lower receivers
- Simplified Installation Features - Threaded take-down pin detent hole accepts included 6-32 set screw for easy installation, threaded bolt catch pin for secure mounting
- Multi-Caliber Marked - "MULTI" caliber marking provides flexibility for various AR-15 chamberings
- Mil-Spec Hard-Coat Anodizing - Type 3 Class 2 anodizing per Mil-8625 specifications delivers superior corrosion resistance and wear properties
Technical Specifications
| Specification |
Details |
| Material |
7075-T6 Aircraft Grade Billet Aluminum |
| Finish |
Matte Black Hard-Coat Anodized (Mil-8625 Type 3 Class 2) |
| Weight |
2.5 lbs (complete assembly) |
| Caliber Marking |
MULTI |
| Magazine Compatibility |
Accepts all standard AR-15 magazines |
| Pistol Brace |
SB Tactical SBA3 Adjustable |
| Trigger |
ALG Advanced Combat Trigger |
| Safety Selector |
Radian Ambidextrous |
| Grip |
B5 Systems |
| Buffer System |
Proprietary H2 Weight Buffer (included) |
| Manufacturing |
Made in USA |
| Warranty |
Lifetime |
Frequently Asked Questions
What makes the SA-15 different from folding stock adapters?
The SA-15 features a patented built-in folding mechanism integrated directly into the lower receiver, eliminating the need for bulky aftermarket folding stock adapters. This integrated design saves over half a pound compared to popular adapter systems while maintaining a cleaner, more streamlined profile. You get the benefits of a folding AR-15 without the added weight, complexity, or potential failure points of adapter-based systems.
Is the SA-15 compatible with standard AR-15 upper receivers?
Yes, the SA-15 is designed to work with most standard AR-15 upper receivers and aftermarket components. The lower features standard mil-spec dimensions and threading, ensuring broad compatibility across the AR-15 platform. The included upper tension screw allows you to fine-tune the fit between upper and lower receivers for a tight, rattle-free connection.
Can I fire the weapon with the stock folded?
No, the SA-15 should only be fired with the folding mechanism in the extended and locked position. The folding feature is designed for compact storage and transport, not for firing in the folded configuration. Always ensure the mechanism is fully extended and locked before attempting to fire.
What buffer system does the SA-15 use?
The SA-15 ships with a proprietary H2 weight buffer specifically designed for the folding lower receiver. This buffer is optimized to work with the integrated folding mechanism and should be used with the lower for proper function and reliability. Standard AR-15 buffer tubes and springs are not compatible with the SA-15's unique design.
Does the SA-15 accept standard AR-15 magazines?
Yes, the SA-15 features a precision-machined magazine well that accepts all standard AR-15 magazines including PMAG, GI magazines, and aftermarket options. The beveled feed lips provide smooth magazine insertion and positive lockup. Consider pairing with our PMAG Gen 2 +5 Extension or PMAG Gen 3 +5 Extension for increased capacity.
What trigger comes installed in the SA-15?
The SA-15 comes complete with an ALG Advanced Combat Trigger (ACT), a high-quality mil-spec style trigger designed by Geissele Automatics founder Bill Geissele. The ALG ACT offers a smooth, consistent trigger pull with a combat-appropriate pull weight, making it ideal for both tactical applications and recreational shooting.
Is the SA-15 legal in my state?
Firearms laws vary significantly by state and locality. The SA-15 is a complete lower receiver with a pistol brace and is subject to all applicable federal, state, and local laws. It is the buyer's responsibility to ensure compliance with all applicable laws in their jurisdiction. We recommend consulting with a local firearms attorney or your state's firearms regulatory agency if you have questions about legality in your area.
Can I replace the SBA3 brace with a different brace or stock?
The SA-15 is designed to work with the included SB Tactical SBA3 brace and proprietary buffer system. Due to the integrated folding mechanism and specialized buffer tube design, the SA-15 is not compatible with standard AR-15 buffer tubes, stocks, or most aftermarket braces. The included SBA3 brace provides excellent adjustability and comfort while maintaining the compact profile the SA-15 is designed for.
What is the warranty on the SA-15?
The SA-15 Complete Folding Lower Receiver is backed by Shield Arms' 100% lifetime warranty. We stand behind our products with complete confidence in their quality and performance. If you experience any manufacturing defects or issues with your SA-15, we'll make it right.
How much shorter is the SA-15 when folded?
The folding mechanism significantly reduces the overall length of your AR-15 build when folded, making it much more compact for storage and transport. The exact length reduction depends on your specific upper receiver and barrel configuration, but the folding feature typically reduces overall length by approximately 7-8 inches, making it ideal for vehicle storage, backpacks, and discreet cases.
Does the SA-15 require any special tools for installation?
The SA-15 comes as a complete lower receiver with all components pre-installed, so minimal assembly is required. You'll simply need to attach your AR-15 upper receiver using standard take-down and pivot pins. The included threaded detent holes with set screws actually make installation easier than traditional lower receivers. All necessary hardware is included, and the process can be completed with basic tools. For detailed guidance, visit our installation guides.
What calibers can I build with the SA-15?
The SA-15 is marked "MULTI" and accepts standard AR-15 magazines, making it compatible with any caliber that uses the AR-15 platform and standard magazine well dimensions. Common options include 5.56 NATO/.223 Remington, .300 Blackout, and other AR-15 compatible chamberings. Always ensure your complete build complies with all applicable federal, state, and local laws.
Who Should Buy the SA-15 Complete Folding Lower Receiver
- Vehicle Carry Enthusiasts - Shooters who need a compact AR-15 solution for truck, car, or ATV storage
- Backpack Gun Builders - Outdoor enthusiasts and hikers looking for a portable defensive platform
- Compact Storage Advocates - Gun owners with limited safe space who want to maximize storage efficiency
- Home Defense Users - Homeowners seeking a full-size AR-15 that stores compactly in strategic locations
- Weight-Conscious Builders - Shooters who want folding capability without the weight penalty of adapter systems
- Travel Shooters - Firearms enthusiasts who transport their AR-15 frequently and value compact dimensions
- Quality Component Seekers - Builders who appreciate premium components like ALG triggers and Radian controls
- AR-15 Enthusiasts - Platform enthusiasts looking for innovative, American-made solutions
Installation & Setup
The SA-15 Complete Folding Lower Receiver ships fully assembled with all components installed and ready to pair with your AR-15 upper receiver. Simply attach your upper using standard take-down and pivot pins, and you're ready to go. The included threaded detent holes with set screws actually simplify the installation process compared to traditional lower receivers. The upper tension screw behind the grip allows you to fine-tune the fit between upper and lower for a tight, precise feel. For detailed installation instructions and helpful tips, visit our comprehensive installation guides.
Related Products & Accessories
- Magpul PMAG Gen 2 +5 Extension - Increase your magazine capacity by 5 rounds for extended range sessions. Perfect for adding capacity to your existing PMAG Gen 2 magazines without the bulk of larger magazines.
- Magpul PMAG Gen 3 +5 Extension - Boost your PMAG Gen 3 capacity by 5 rounds. Ideal for competition, training, or extended shooting sessions where every round counts.
Made in USA with Lifetime Warranty
The SA-15 Complete Folding Lower Receiver is proudly designed, engineered, and manufactured in the United States using American materials and craftsmanship. Every SA-15 undergoes rigorous quality control inspection to ensure it meets our exacting standards for precision and performance. We back every SA-15 with our 100% lifetime warranty - if you ever experience any issues with manufacturing defects or material failures, we'll make it right. When you choose Shield Arms, you're choosing American innovation, quality, and support that lasts a lifetime.
