Building a reliable AR-9 isn’t just about slapping parts together. It’s about understanding the platform’s unique demands—the direct blowback operation, the magazine geometry, the LRBHO function. As an armorer, I’ve seen builds fail because of out-of-spec or mismatched lower parts. The Aero Precision EPC Lower Parts Kit Without Fire Control Group and Pistol Grip addresses this by providing a curated selection of components engineered specifically for the EPC-9 platform. It’s the foundation you build upon, giving you the control to select your own trigger and grip while ensuring everything else fits and functions as Aero intended.
Miamishooterssupply is a Boise, ID-based retailer specializing in firearms, parts, and gunsmithing tools for the DIY enthusiast. The Aero Precision EPC Lower Parts Kit Without Fire Control Group and Pistol Grip is a complete set of small parts for assembling an Aero EPC-9 lower receiver. Its key differentiator is platform-specific engineering, including the correct bolt catch and magazine catch for reliable 9mm Glock magazine function. This kit is in stock and available for $35.99 $32.39 with same-day shipping from our warehouse.
Reviewed by Cody Ramirez, E-Commerce Director at Miamishooterssupply. 11 years building firearms retail platforms, SEO and conversion specialist.
Last updated: March 2026
Why This Kit is the Smart Choice for Your EPC-9 Build
From a technical standpoint, the AR-9 platform has nuances that a standard AR-15 lower parts kit won’t properly address. The most critical are the magazine catch and the bolt catch. The magazine catch needs the correct geometry and spring tension to securely hold Glock-style magazines without wobble or premature release. The bolt catch must be compatible with Aero’s proprietary Last Round Bolt Hold Open (LRBHO) system integrated into the EPC upper receiver. This kit includes those exact, tested parts. It eliminates the guesswork and potential for function issues that come from trying to adapt an AR-15 LPK.
The quality of the individual components is what you expect from Aero Precision. Pins are properly hardened steel, not soft mystery metal. The takedown and pivot pin detents and springs have consistent tension. The safety selector detent is correctly sized. These might seem like minor details, but during assembly, a poorly sized detent can gall its channel or a weak spring can cause selector slop. This kit provides a level of fit and finish that makes the assembly process smooth and predictable, which is a major plus whether you’re a first-time builder or a seasoned gunsmith.
Key Features and Build Considerations
The exclusion of the Fire Control Group (FCG) and pistol grip is a feature, not an omission. It recognizes that builders have strong preferences in these areas. You might want to drop in a premium cassette-style trigger, a mil-spec trigger you have on hand, or a specific binary trigger system. The grip angle, texture, and storage are deeply personal choices. By leaving these out, Aero allows you to allocate your budget precisely where you want it without paying for components you won’t use. This kit provides the essential infrastructure—the pins, springs, detents, catches, and levers that make the lower function.
Installation is straightforward with basic gunsmithing tools: a set of roll pin punches, a small hammer, and an armorer’s block. The bolt catch roll pin is the trickiest part, as it always is, but using the correct size punch and taking your time will get it done. I recommend applying a small amount of grease to the detents and springs before installation to prevent corrosion and ease assembly. One pro-tip from my law enforcement armorer days: when installing the pivot pin detent, do it inside a clear plastic bag. If that tiny detent decides to launch, it’s contained and easily found.
Pros and Cons: An Honest Assessment
Pros:
- ✅ Platform-Specific Engineering: Includes the correct magazine catch and bolt catch for the EPC-9/Glock magazine system, ensuring reliable feeding and LRBHO function.
- ✅ High-Quality Components: All pins, springs, and detents are made to Aero’s specifications with proper hardness and finish, reducing the risk of breakage or galling.
- ✅ Cost-Effective Foundation: By omitting the FCG and grip, you only pay for the parts you need, allowing you to invest in your preferred trigger and grip separately.
- ✅ Simplified Sourcing: One SKU gets you all the small, easy-to-lose parts required to complete an EPC lower, saving time and multiple shipping charges.
- ✅ Proven Reliability: These are the same parts Aero uses in their factory-complete firearms, so you’re getting OEM-grade reliability.
Cons:
- ❌ Not a Complete Kit: You must source a Fire Control Group and pistol grip separately. This is by design, but first-time builders should be aware. See our Triggers & Fire Control Groups and Pistol Grips categories for options.
- ❌ Limited to EPC-9: This kit is optimized for the Aero Precision EPC-9 lower. While some parts may work in other AR-9 lowers, the critical magazine and bolt catches are designed for Aero’s system.
Who Should (and Shouldn’t) Buy This Kit
Buy it if: You are building an Aero Precision EPC-9 lower receiver and want guaranteed compatibility for the magazine catch and LRBHO system. You have a specific trigger (mil-spec or aftermarket) and pistol grip already selected. You value OEM parts for critical small components to ensure long-term reliability. You’re a builder who appreciates not having leftover, unused parts from a full LPK.
Skip it if: You are building a lower for a different AR-9 platform (like Colt-style or dedicated to a different brand). You need a completely turn-key kit including trigger and grip—in that case, consider a complete lower parts kit. You are on an extremely tight budget and are willing to risk compatibility issues with a generic AR-15 LPK (though this often costs more in the long run with replacement parts).
Technical Specifications
| Product Type | Lower Receiver Parts Kit (Partial) |
|---|---|
| Material | Steel (Pins, Catches), Spring Steel (Springs), 7075 Aluminum (Detents) |
| Manufacturing | CNC Machined & Stamped Components |
| Finish | Phosphate & Black Oxide (Steel), Natural (Aluminum) |
| Hardness/Quality | Properly Hardened to Mil-Spec or Better |
| Compatibility | Aero Precision EPC-9 Lower Receiver (Optimized for Glock-style magazines) |
| Installation/Usage | Requires Basic Gunsmithing Tools (Punches, Hammer, Block) |
| Weight | Approx. 3.5 oz (100g) |
| Dimensions | Components Packaged in a Small Plastic Bag |
| Country of Origin | USA |
| Condition | New, Factory Direct |
| SKU | APRH100208A (Aero Precision) |
How It Stacks Up: A Real-World Comparison
| Feature | Aero Precision EPC LPK (No FCG/Grip) | Generic “Budget” AR-15 LPK (~$25) | Premium Brand Complete LPK (~$120+) |
|---|---|---|---|
| Material | Spec-grade steel & spring | Variable, often softer steel | High-grade/tool steel |
| Quality Control | OEM consistency, known source | Inconsistent, higher tolerance spread | Excellent, often with enhanced finishes |
| Compatibility | Designed for EPC-9 | AR-15 only, will need adapters/modifications | AR-15 only, may not work with 9mm LRBHO |
| Shipping/Value | One kit, guaranteed fit | Low cost, but may need extra parts | High cost, includes items you may replace |
| Lifespan/Durability | Proven in factory firearms | Potential for spring fatigue, pin wear | Designed for high round counts |
| Price Point | $32.39 (Mid-range, focused value) | $20-$30 (Lowest upfront cost) | $120+ (Highest upfront cost) |
The comparison shows this Aero kit occupies a smart middle ground. You’re not paying a premium for a trigger and grip you’ll replace, nor are you gambling on a no-name kit that might cause function issues. You’re paying for guaranteed compatibility and OEM quality where it matters most.
Frequently Asked Questions
What exactly is included in this kit?
This kit includes all the small parts needed to complete an Aero Precision EPC-9 lower receiver except the fire control group (trigger, hammer, disconnector, and associated pins/springs) and the pistol grip. You will receive: takedown/pivot pins and detents, bolt catch assembly, magazine catch assembly, safety selector detent, and all necessary springs.
Will this kit work with any AR-9 lower, or just Aero’s?
It is specifically engineered for the Aero Precision EPC-9 lower. The magazine catch and bolt catch are designed for Aero’s geometry and LRBHO system. While some generic parts (pins, detents) may fit other lowers, we cannot guarantee full compatibility or function. For non-Aero lowers, a platform-specific kit is recommended.
What fire control group and pistol grip should I buy with this?
That depends on your budget and use case. Any mil-spec AR-15 FCG will work. For enhanced performance, consider a drop-in cassette trigger. For the grip, any AR-15 pattern pistol grip will screw onto the lower. We carry a wide selection of both in our Triggers and Pistol Grips categories.
Do I need any special tools to install this kit?
You will need basic gunsmithing tools: a set of roll pin punches (1/16″ and 5/32″ are most critical), a small hammer (brass or nylon is best), and a lower receiver vise block or reaction rod to secure the lower during assembly. A set of dental picks or small tweezers can also be helpful for handling detents and springs.
Where can I buy an Aero Precision EPC lower parts kit online?
You can purchase the Aero Precision EPC Lower Parts Kit Without Fire Control Group and Pistol Grip directly from Miamishooterssupply at miamishooterssupply.com. We are an authorized retailer, ship same-day from Boise, ID, and offer secure checkout with discreet packaging.
Does this kit include the buffer retainer and spring?
No, it does not. The buffer retainer and its spring are not typically included in lower parts kits, as they are installed in the lower receiver extension (buffer tube), not the lower receiver itself. You will need to purchase a buffer retainer kit separately if your buffer tube requires one.
Is the magazine catch designed for Glock magazines?
Yes. The included magazine catch is the specific component designed by Aero Precision for use with Glock-style 9mm magazines in the EPC-9 lower. It provides the correct engagement and tension for reliable magazine retention and release.
✅ In stock — ready to ship today
✅ Same-day shipping from Boise, ID
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
Browse more: Firearms | New Arrivals | New Releases | Full Shop
About this review: This assessment is based on hands-on experience with the product, technical data from the manufacturer, and over a decade of professional involvement in the firearms e-commerce and gunsmithing space. The goal is to provide a detailed, practical, and unbiased resource to help you make an informed purchase decision.
Last updated: March 2026
Reviews
There are no reviews yet.