80% .308 Easy Jig® Gen 1
Video review
Expert review
About this product
The 80% .308 Easy Jig® Gen 1 is a CNC-machined aluminum fixture that guides precise milling of 80% lower receivers for AR-10 platform firearms. It eliminates guesswork with integrated depth control and maintains ±0.003 inch tolerance across critical surfaces. This jig represents the first generation of dedicated .308 tooling for home builders seeking rifle-caliber customization.
What is the 80% .308 Easy Jig® Gen 1 used for?
This jig completes 80% .308 AR lowers by guiding milling operations to final specifications. Its aluminum construction resists deflection during drilling and routing, maintaining receiver geometry within functional tolerances. The integrated depth gauge prevents over-milling that would scrap a $150 blank.
How does the 80% .308 Easy Jig® Gen 1 compare to the 80% AR-15 Easy Jig® Gen 1?
The .308 version accommodates larger LR-308/AR-10 lower dimensions while sharing the same fundamental design philosophy. It requires 18% more material removal than the AR-15 jig due to the .308 lower's increased mass, but both maintain identical ±0.003 inch tolerance standards. For builders moving from AR-15 to AR-10 platforms, this provides consistent methodology across calibers.
What does it weigh and what are the dimensions?
The jig weighs 2.1 pounds (952 grams) with overall dimensions of 8.5 x 4.25 x 3 inches. This mass provides stability during milling operations without being cumbersome on drill press tables. The aluminum construction contributes to both durability and heat dissipation during extended use.
Who is this NOT for?
This jig serves no purpose for builders working with finished lowers or pistol-caliber platforms. Those seeking to complete 308 80% Lower – Billet will find it essential, while owners of completed firearms require zero milling tools. The Gen 1 design also lacks compatibility with Gen 2 tooling like the 5/16" High Speed End Mill for Easy Jig® Gen 2.
What's in the box?
The package contains the main jig body, mounting hardware, and integrated depth gauge—no cutting tools included. Builders must supply their own 5/16" end mill and appropriate drill bits. The omission of cutting tools keeps the base price down but requires separate tool acquisition totaling approximately $40-60.
Is the 80% .308 Easy Jig® Gen 1 worth it at $0.0?
At any price point, this jig provides measurable value by preventing costly errors in receiver machining. When paired with a .308 80% Lower and LR-308/AR-10 Lower Parts Kit, it enables complete lower construction for approximately 60% of commercial retail cost. The jig's reusable nature makes it economically viable even for single-use scenarios.
Specs at a glance
Pros & cons
What works
- Maintains ±0.003 inch tolerance - critical for reliable firearm function
- 2.1 pound mass reduces vibration during milling operations
- Integrated depth gauge prevents over-milling that scraps $150+ lowers
- CNC aluminum construction withstands 100+ lower completions
Trade-offs
- No included cutting tools - requires separate $40-60 tool purchase
- Gen 1 design incompatible with newer Gen 2 tooling systems
- Aluminum construction shows wear after 50+ uses requiring inspection
- Limited to .308 platform only - no multi-caliber functionality
Key attributes
| Compatibility | 80% .308 AR lowers |
| Material | CNC aluminum |
| Weight | 2.1 lb |
| Tolerance | ±0.003 inch |
| Platform | AR-10/LR-308 |
| Required Tools | 5/16" end mill + drill press |
Specifications
| Compatibility | 80% .308 AR lowers |
| Material | CNC aluminum |
| Jig Type | Easy Jig Gen 1 |
| Features | Integrated depth gauge |
| Usage | Home milling with drill press/router |
Best for
- Finishing 80% .308 AR lower receivers
- Custom AR-10 builds
- At-home firearm manufacturing
Materials
- Aluminum
What's in the box
- Easy Jig Gen 1 unit
Care
Frequently asked questions
- Is it compatible with polymer .308 lowers?
- No, this jig is designed specifically for aluminum 80% lowers with LR-308/AR-10 footprint. Polymer lowers require different fixturing and milling techniques due to material flexibility and lower melting point. For polymer-specific guidance, consult our <a href="/blog/best-drill-bits-for-polymer-80-percent-lower-milling/">Precision Tested: The Best Drill Bits for Polymer 80% Lower Milling</a> article.
- Does it work with Gen 2 end mills?
- No, the Gen 1 jig requires standard 5/16" end mills, not the specialized tools designed for Gen 2 systems. Using Gen 2 tooling in this jig will result in improper cutting geometry and potential fixture damage. Always verify tool compatibility before beginning milling operations.
- How long does shipping take?
- Standard shipping processes orders within 2 business days with transit times of 3-5 days continental US. Expedited options reduce processing to 1 business day with 2-day air delivery. International shipments require 10-15 days plus customs processing.
- Can I return it if I damage my lower?
- No, the jig is non-returnable once used due to potential contamination with metal shavings and liability concerns. Proper technique following included instructions typically prevents damage, but we recommend practicing on inexpensive material first. Our <a href="/blog/how-to-check-80-lower-receiver-buffer-tube-threads/">buffer tube thread checking guide</a> helps verify proper alignment before final assembly.