Description
The ATI Ar-15 Milsport Aluminum Stripped Multi-Cal Lower is the foundational component for building a custom AR-15 rifle or pistol. It’s a stripped, serialized receiver made from 7075-T6 aluminum, requiring the end user to install the trigger, safety, magazine catch, and other internal parts. This platform is designed for multi-caliber compatibility, allowing you to build a firearm chambered in .223/5.56, .300 Blackout, 6.5 Grendel, and more, starting from a single, affordable receiver. It’s the starting point for a truly personalized firearm.
Key Features
- 7075-T6 Aluminum Forging: Built to mil-spec standards for durability and strength, not a weaker alloy.
- Multi-Caliber Compatibility: The core platform for builds in .223/5.56, .300 BLK, 6.5 Grendel, 7.62×39, and other cartridges that use a standard AR-15 magazine well.
- Stripped & Ready for Customization: Arrives without internal fire control parts, giving you complete control over your trigger, safety selector, and bolt catch choices.
- Mil-Spec Compatibility: This is the key feature—it accepts all standard, mil-spec AR-15 internal parts and accessories. No proprietary headaches here.
- Anodized Finish: Provides a hard, corrosion-resistant surface ready for immediate assembly or further finishing.
Specifications & Details
| Material | 7075-T6 Aluminum Forging |
| Finish | Matte Black Anodized |
| Compatibility | Mil-Spec AR-15 Components |
| Fire Control | Stripped (Parts Not Included) |
| Caliber Designation | Multi |
| Weight | Approx. 8.5 oz (lower only) |
Look, when it comes to building a reliable rifle for home defense or the range, the foundation is everything. This ATI lower is that foundation. It’s engineered to work with standard parts kits from companies like CMMG, Aero Precision, or Palmetto State Armory, so sourcing your trigger guard or pivot pin detent is straightforward. The anodizing is consistent, and the critical pin holes and threading are precisely machined. At a price point of $57.71, it represents a significant value, allowing you to allocate more of your budget to a quality barrel or optic. Remember, an FFL transfer is required for this firearm purchase, a standard and secure step in the process.
Who This Lower Receiver Is For
This is for the builder. It’s for the shooter who knows exactly what trigger pull weight they want, or who has a specific pistol brace or stock in mind. It’s for the Missouri hunter wanting a lightweight 6.5 Grendel upper for deer season, or for the practical shooter assembling a dedicated .300 Blackout home defense firearm with a suppressor in mind. It’s also an excellent first build project due to its straightforward compatibility and approachable cost.
Pros & Cons
Pros: Exceptional value for a forged 7075-T6 receiver. True mil-spec dimensions mean parts fit out of the box without modification. The multi-caliber designation offers long-term flexibility for your next upper receiver. It’s a no-frills, functional starting point proven by countless builds.
Cons: As a stripped lower, it requires additional investment and time to assemble with a lower parts kit, buffer kit, and stock. The finish, while durable, is a basic matte anodize. That said, for a functional build where the focus is performance over aesthetics, it’s more than sufficient.
Frequently Asked Questions
Q: What parts do I need to complete this lower receiver?
A: You will need a Lower Parts Kit (LPK), which includes the trigger, hammer, safety selector, magazine catch, and all springs and detents. You also need a buffer tube kit (buffer tube, buffer, spring, castle nut, end plate) and your choice of stock or pistol brace.
Q: Is this lower compatible with any AR-15 upper receiver?
A: Yes, it is designed to be compatible with any standard mil-spec AR-15 upper receiver. Proper headspacing should always be verified when pairing a new barrel with a bolt carrier group, but the upper-to-lower fit is standardized.
Q: Can I build a pistol or a rifle with this lower?
A: You can build either, but the initial configuration is critical for legal compliance. If you intend to build an AR pistol (with a barrel under 16″ and a pistol brace), you must first assemble it as a pistol. It is available at firearms-missouri.com for Missouri residents and nationwide, and we can guide you through the compliant process.
Ready to start your build with a solid, no-nonsense foundation? This ATI Milsport lower is in stock and ready for your FFL.
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