What is the SA-15 Stripped Folding Lower Receiver?
Shield Arms' patented folding lower receiver with integrated folding mechanism - NO ADAPTER required. Unlike traditional folding adapters, the folding mechanism is built directly into the billet aluminum receiver for a lighter, stronger, more reliable design. Perfect for building custom folding AR-15 rifles and pistols.
- Key Innovation: No folding adapter needed - mechanism integrated into receiver
- Construction: 7075-T6 billet aluminum - stronger than forged
- Use: Build custom folding AR-15 rifles or pistols (5.56, .300 BLK, 9mm, etc.)
Revolutionary Folding Technology - No Adapter Required
The Shield Arms SA-15 Stripped Folding Lower Receiver represents a revolutionary advancement in AR-15 design. Unlike traditional folding AR-15s that require bulky, heavy folding adapters installed between the upper and lower receivers, the SA-15 features a patented folding mechanism integrated directly into the lower receiver.
This innovative design eliminates the need for separate folding adapters, resulting in a lighter, stronger, more compact folding rifle or pistol. The SA-15 is a complete mil-spec lower receiver that accepts all standard AR-15 parts, while providing true folding capability for compact storage and transport.
Build your dream folding AR-15 with complete freedom to choose your upper receiver, barrel length, caliber, furniture, and accessories. Compatible with 5.56 NATO, .300 Blackout, 9mm, and other AR-15 calibers.
Key Features & Advantages
Patented Integrated Folding Mechanism
- No adapter required - folding mechanism built into the receiver itself
- Lighter weight - eliminates heavy folding adapter (typically .5 lbs or more)
- Stronger design - fewer points of failure than adapter systems
- Compact folding - folds tighter than adapter-based systems
- Reduced complexity - simpler build process, fewer parts
- Improved balance - weight distributed optimally without adapter
Premium Construction
- 7075-T6 billet aluminum - aerospace-grade material, stronger than forged receivers
- Precision CNC machined - tight tolerances for perfect fit and function
- Mil-spec dimensions - accepts all standard AR-15 parts and components
- Flared magazine well - faster, easier reloads
- Integral trigger guard - streamlined appearance, enhanced strength
- Made in USA - precision manufactured in Bigfork, Montana
Versatile Build Platform
- Multiple caliber compatibility - 5.56 NATO, .300 Blackout, and more
- Rifle or pistol builds - works with any barrel length configuration
- Standard AR-15 parts - buffer tube, stock, grip, trigger, LPK all compatible
- Upper receiver compatibility - works with any mil-spec AR-15 upper
- Custom configurations - build exactly what you want
Custom Cerakote Finish Options
We now offer custom cerakote options on our stripped FLR. These patterns are truly unique, with no two firearms appearing identical. Choose from three distinctive finish styles:
- Fallout: Post-apocalyptic inspired pattern with distressed earth tones and tactical aesthetics
- Montana Mud: Natural camouflage pattern blending browns, tans, and earth tones for wilderness environments
- Pineland: Woodland-inspired multi-tone pattern optimized for varied terrain
All Cerakote finishes provide exceptional durability, corrosion resistance, and abrasion protection while giving your pistol a distinctive appearance that stands out from factory finishes.
SA-15 Folding Lower vs Traditional Folding Adapters
| Feature |
SA-15 Folding Lower |
Traditional Folding Adapter |
| Folding Mechanism |
Integrated into receiver (patented) |
Separate adapter between upper/lower |
| Additional Parts Required |
None - folding built-in |
Folding adapter ($200-400) |
| Weight |
Lighter (no adapter weight) |
Heavier (.5 lbs or more for adapter) |
| Folded Length |
More compact |
Longer (adapter adds length) |
| Complexity |
Simpler - fewer parts |
More complex - additional component |
| Points of Failure |
Fewer (integrated design) |
More (adapter joints) |
| Build Process |
Standard AR-15 build |
Requires adapter installation |
| Balance |
Optimal weight distribution |
Adapter shifts center of gravity |
The Bottom Line: The SA-15's integrated folding design eliminates the compromises of traditional folding adapters, resulting in a lighter, stronger, more compact folding AR-15 at a competitive price point.
Technical Specifications
| Material |
7075-T6 Billet Aluminum |
| Manufacturing |
CNC Machined |
| Finish |
Mil-Spec Hard Coat Anodized (Type III, Class 2) |
| Dimensions |
Mil-Spec AR-15 (accepts all standard parts) |
| Folding Mechanism |
Patented Integrated Design |
| Trigger Group |
Accepts all mil-spec AR-15 triggers and LPKs |
| Buffer System |
Proprietary buffer included |
| Magazine Well |
Flared for enhanced reloads |
| Trigger Guard |
Integral (built into receiver) |
| Serial Number |
Engraved (ATF compliant) |
| FFL Required |
Yes (firearm lower receiver) |
| Caliber Compatibility |
5.56 NATO, .300 BLK, 9mm, .22 LR, others |
| Upper Compatibility |
All mil-spec AR-15 uppers |
| Warranty |
100% Lifetime |
| Made In |
USA (Montana) |
| SKU |
SA-FLR-STRIPPED |
What's Included
The SA-15 Stripped Folding Lower Receiver includes:
- (1) SA-15 Stripped Lower Receiver with integrated folding mechanism and buffer
- Serialized and ATF compliant - ready for FFL transfer
Not Included (Standard AR-15 Build Parts Required)
To complete your build, you'll need:
- Lower Parts Kit (LPK) - trigger, hammer, springs, pins, etc.
- Buffer tube, buffer spring
- Stock or pistol brace
- Pistol grip
- AR-15 upper receiver assembly
- Bolt carrier group
- Charging handle
- Magazine
Note: This is a stripped lower receiver - you provide all other components for your custom build.
Build Options & Compatibility
Caliber Options
The SA-15 Folding Lower is compatible with multiple AR-15 calibers:
- 5.56 NATO / .223 Remington - Standard AR-15 rifle caliber
- .300 Blackout - Subsonic and supersonic capability
Configuration Options
- Pistol Build - Barrel under 16", requires pistol brace (SB Tactical, etc.)
- Rifle Build - Barrel 16" or longer, use with standard stock
- SBR (Short Barreled Rifle) - Barrel under 16" with stock, requires ATF Form 1 and tax stamp
Recommended Parts
The SA-15 works with all mil-spec AR-15 parts. Shield Arms recommends:
- Triggers: ALG Advanced Combat Trigger, Geissele, LaRue MBT, Trigger Tech
- Stocks/Braces: SB Tactical SBA3/SBA4, B5 Systems SOPMOD, Magpul CTR
- Grips: B5 Systems Type 23, Magpul MOE/K2, BCM Gunfighter
- Charging Handles: Radian Raptor, Geissele ACH, BCM Gunfighter
FFL Transfer & Shipping Information
The SA-15 Stripped Lower Receiver is a firearm lower receiver and requires transfer through a Federal Firearms Licensed (FFL) dealer.
How FFL Transfer Works
- Place Your Order: Purchase the SA-15 lower receiver through Shield Arms
- Select Your FFL: Choose your preferred local FFL dealer during checkout (or provide FFL information after purchase)
- FFL Documentation: Your chosen FFL will send their license to Shield Arms
- Shipping: Shield Arms ships the lower receiver directly to your FFL dealer
- Pickup: Visit your FFL to complete ATF Form 4473 background check and take possession
Important Notes
- Must comply with all federal, state, and local firearms laws
- Your FFL may charge a transfer fee (typically $25-50)
- Shipping time: 3-7 business days after FFL documentation received
- Cannot be shipped to prohibited states/localities - check your local laws
Need help finding an FFL? Shield Arms can assist you in locating an FFL dealer near you. Contact customer service after placing your order.
Frequently Asked Questions
What makes the SA-15 different from other folding AR-15s?
The SA-15 features a patented integrated folding mechanism built directly into the lower receiver. Traditional folding AR-15s require a separate folding adapter installed between the upper and lower receivers, adding weight, complexity, and length. The SA-15 eliminates the adapter entirely, resulting in a lighter, stronger, more compact folding design.
Can I fire the SA-15 while folded?
No. Like all folding AR-15 designs, the SA-15 cannot be fired while folded. The folding mechanism is designed for compact storage and transport only. You must unfold and lock the receiver before firing.
What parts do I need to complete the build?
The SA-15 is a stripped lower receiver, so you'll need all standard AR-15 build parts: lower parts kit (LPK), buffer tube/spring, stock or brace, pistol grip, upper receiver assembly, bolt carrier group, charging handle, and magazine. It's a standard AR-15 build process with the added benefit of the integrated folding mechanism.
Is the SA-15 stronger than a forged lower receiver?
Yes. The SA-15 is CNC machined from 7075-T6 billet aluminum, which can be stronger and more durable than forged 7075-T6 aluminum depending on the design. Billet construction allows for tighter tolerances, enhanced features (like the flared magazine well and integral trigger guard), and a high strength-to-weight ratio.
What calibers can I build with the SA-15?
The SA-15 accepts all standard AR-15 upper receivers, so you can build in any AR-15-compatible caliber: 5.56 NATO, .300 Blackout, and others. Simply pair with the appropriate upper receiver and bolt carrier group for your chosen caliber.
Can I build this as a pistol or does it have to be a rifle?
You can build either. With a barrel under 16" and a pistol brace, it's classified as a pistol. With a barrel 16" or longer and a stock, it's a rifle. If you want a barrel under 16" with a stock, you'll need to file ATF Form 1 and pay the tax stamp to register it as an SBR (Short Barreled Rifle).
Does the folding mechanism affect reliability?
No. When unfolded and locked, the SA-15 functions identically to a standard AR-15 lower receiver. The folding mechanism is robust and designed for thousands of folding cycles without affecting reliability or accuracy.
How much shorter is the SA-15 when folded?
Folded length depends on your complete build configuration, but typically reduces overall length by approximately 8-10 inches. For example, a 16" rifle that's 35" overall length unfolded would be approximately 25-27" when folded.
Is this legal in my state?
The SA-15 folding lower receiver is legal in most states. However, some states have restrictions on AR-15 style firearms or features. Check your state and local laws before purchasing. Shield Arms cannot ship to prohibited jurisdictions.
What is the warranty on the SA-15?
Shield Arms backs the SA-15 Stripped Folding Lower Receiver with a 100% Lifetime Warranty against manufacturing defects. If you experience any issues with materials or workmanship, Shield Arms will repair or replace it free of charge.
Who Should Buy the SA-15 Folding Lower?
- Custom AR-15 Builders - Want a unique folding capability without adapters
- Truck/Vehicle Gun Builds - Compact folded length ideal for vehicle storage
- Backpack/Travel Guns - Folds for discreet transport in bags or cases
- Home Defense - Compact storage with quick deployment capability
- Competition Shooters - Easier transport to matches and competitions
- Innovation Enthusiasts - Appreciate cutting-edge firearm design
- Minimalists - Want folding capability without heavy adapters
- DIY Builders - Enjoy building custom firearms from components
Summary: Is the SA-15 Folding Lower Right for You?
The Shield Arms SA-15 Stripped Folding Lower Receiver represents a revolutionary advancement in AR-15 design. By integrating the folding mechanism directly into the lower receiver, Shield Arms has eliminated the compromises of traditional folding adapters while maintaining full mil-spec compatibility.
Key Advantages:
- Patented integrated folding - no adapter required
- Lighter weight than adapter-based systems
- Stronger 7075-T6 billet aluminum construction
- More compact folded length
- Standard AR-15 build process and parts compatibility
- Multiple caliber options (5.56, .300 BLK, 9mm, etc.)
- Rifle or pistol configurations
- Made in USA with lifetime warranty
Perfect for: Custom builders, truck gun builds, backpack rifles, home defense, competition transport, and anyone who values compact storage without compromising on strength or reliability.
Ready to build your folding AR-15? The SA-15 Stripped Folding Lower Receiver provides the innovative foundation for your dream build. Order now and experience the future of folding AR-15 design.
