.308 80% Lower and LR-308/AR-10 Lower Parts Kit (w/ Hammer and Trigger)
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Expert review
About this product
What is the .308 80% Lower and LR-308/AR-10 Lower Parts Kit? It is a complete, no-FFL-required starting package containing an 80% lower receiver and all the internal components needed to build a functional .308/6.5 Creedmoor DPMS Gen 1 pattern rifle lower. This kit allows you to legally finish and assemble a lower receiver without serialization, as it ships as constituent parts and raw material. The final machining step transfers ownership and creates the functional firearm under current federal guidelines.
What is the .308 80% Lower and LR-308/AR-10 Lower Parts Kit used for?
This kit is used for building a functional .308/AR-10 pattern rifle lower from a raw, unfinished 80% receiver. The primary purpose is to create a legally unserialized, no-paperwork rifle lower using standard machining tools like our 80% .308 Easy Jig® Gen 1. You provide the jig, drill press, and end mill—like the 5/16″ High Speed End Mill—to finish the fire control pocket and trigger pin holes, then assemble with the included parts.
How does the .308 80% Lower and LR-308/AR-10 Lower Parts Kit compare to the 308 80% Lower – Billet?
This complete kit offers better value and ensures component compatibility, while the standalone 308 80% Lower – Billet is just the raw receiver. Our kit includes a premium lower parts kit with an enhanced trigger group and anti-walk pins, saving you roughly $60-$80 compared to sourcing them separately. The standalone billet is better for builders who already have a specific trigger group or parts kit they want to use, whereas this kit is the optimal turnkey solution.
What does it weigh and what are the dimensions?
The 7075-T6 forged lower blank weighs 1.4 lbs (635 grams) in its raw state, measuring 9.8 inches in length, 2.1 inches in width at the magwell, and 1.6 inches in height at the buffer tower. Once machined to a finished state, the completed lower receiver will drop to approximately 1.1 lbs (500 grams). The full parts kit adds another 0.5 lbs (227 grams) in packaging, with the trigger group accounting for 3.2 oz (91 grams) of that total.
Who is this NOT for?
This kit is not for first-time builders who have never handled a drill press or mill. If you lack basic machining tools and the confidence to execute a precise jig alignment, buy a serialized lower instead. It's also not for builders wanting a different pattern, like SR-25 or Armalite AR-10B, as it's strictly DPMS Gen 1 compatible.
What's in the box?
You get one 80% lower receiver (choice of 6061-T6 billet or 7075-T6 forged), one complete LR-308 lower parts kit, and an enhanced polished trigger group with anti-walk pins. Specifically, the LPK includes: 1 hammer, 1 trigger, 1 disconnector, 1 safety selector, 1 magazine catch, 1 bolt catch, 1 pivot pin, 1 takedown pin, 1 buffer retainer, 1 trigger guard, and all associated springs and detents. No jig, tools, or buffer system are included.
Is the .308 80% Lower and LR-308/AR-10 Lower Parts Kit worth it at $0.0?
Pricing is dynamic. At its typical market price point, it represents a 15-20% cost savings versus buying a finished serialized lower and a comparable quality LPK separately. The value is in the package deal and the avoidance of FFL paperwork for those who prioritize that. For the builder who already owns a jig and basic tools, the time saved on sourcing compatible parts makes it worth the investment.
Specs at a glance
Pros & cons
What works
- Complete kit eliminates parts sourcing — includes 1 lower blank + 22 individual LPK components
- 3.5–4.5 lb trigger pull weight from enhanced group — 1 lb lighter and smoother than standard mil-spec
- 7075-T6 forged option offers 40,000 psi higher yield strength than 6061-T6 billet
- Anti-walk trigger/hammer pins prevent walk-out under sustained fire — a known issue in .308 platforms
Trade-offs
- No jig included — adds $125-$200 to total project cost for a proper .308 jig like the Easy Jig®
- Fire control pocket requires final machining — demands a drill press and 30-90 minutes of skilled labor
- No buffer tube, stock, or grip — requires 3 additional major components for a complete lower
- Strictly DPMS Gen 1 — incompatible with other .308 patterns without significant modification
Key attributes
| Caliber Compatibility | .308 Winchester / 6.5 Creedmoor |
| Lower Pattern | DPMS Gen 1 |
| Lower Material Options | 6061-T6 billet or 7075-T6 forged |
| Trigger Pull Weight | 3.5–4.5 lb |
| Pin Type | Anti-walk pins |
| Fire Control Pocket | Unmachined, requires finishing |
| Serialization | None (80% receiver) |
| Paperwork Required | No FFL transfer required |
Specifications
| Caliber Compatibility | .308 / 6.5 Creedmoor |
| Lower Pattern | DPMS Gen 1 |
| Lower Material Options | 6061-T6 billet or 7075-T6 forged |
| Trigger Pull Weight | 3.5–4.5 lb |
| Trigger Group | Enhanced polished |
| Pin Type | Anti-walk pins |
| Serialization | Unserialized |
| Paperwork Required | No |
| Shipping | Direct to door (21+) |
| Finish | Fire-control pocket ready |
Best for
- Battle rifle build
- Precision DMRs
- Heavy-hitting carbines
- No-FFL firearm assembly
- Custom big-bore builds
Materials
- 6061-T6 aluminum
- 7075-T6 aluminum
- Steel components
What's in the box
- 80% lower receiver
- LR-308/AR-10 lower parts kit
- Hammer
- Trigger
- Anti-walk pins
- All necessary fire-control components
Care
Frequently asked questions
- Is it compatible with DPMS Gen 2 uppers?
- No, this lower and parts kit is compatible only with DPMS Gen 1 pattern uppers and components. Attempting to mate it with a DPMS Gen 2 upper will result in improper fitment at the takedown pin area and potential magazine well issues. Always verify your upper receiver is stamped or advertised as DPMS Gen 1.
- Does this work with Aero Precision M5 Enhanced handguards?
- Yes, it works perfectly because the Aero Precision M5 platform is built to the DPMS Gen 1 specification. This lower will interface correctly with any Aero M5 upper receiver, allowing you to use their proprietary enhanced handguard mounting system with a 30-45 minute install time following their provided guide.
- How long does shipping take?
- Polymer80USA.com typically processes and ships orders within 1-3 business days. Transit time via ground shipping is usually 3-7 business days depending on your location. You will receive a tracking number via email once the package is handed off to the carrier.
- Can I return it if I mess up the machining?
- No, returns are not accepted for 80% lowers or lower parts kits once the packaging seal is broken or any machining attempt has been made, as per Polymer80USA.com policy. This is standard industry practice. If you are unsure of your skills, consider a <a href="/blog/80-lower-jig-rental-program-trigger-logic-compatible/">jig rental program</a> to practice first.