The 80% Jig Compatibility Guide

If you've decided to machine an 80% lower or frame to build a custom firearm, you're going to need one critically important tool: An 80% jig. We're covering jig compatibility in this guide -- learn which jig and tooling you need to cut and drill your lower or frame!

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AR-Type 80% Jig Compatibility

AR jigs are designed exclusively for drilling and milling the original 80% lower receiver, made for the AR-15 platform.

AR jigs come in two sizes

AR-15 jigs are designed for 5.56/.223 lowers, which can also chamber rounds like 300 BLK. Most AR-15 jigs are also compatible with 9mm (AR9) lowers.

LR-308 jigs are designed for .308 ("AR-10") lowers, which are physically larger than 5.56/.223 lower. The .308 lower can also chamber rounds like 6.5 Creedmoor and .243 Winchester.

Elite Builder Patriot Jig (AR-15, AR9, AR-10)

The Elite Builder Patriot Jig is compatible with all three types of 80% lowers: AR-15, AR9 and LR-308. This jig is made from aluminum and steel. Its various templates provide guidance for drilling the hammer, trigger, and safety lever pin holes, and for milling the fire control cavity to make room for a lower parts kit.

This jig can complete both aluminum (billet or forged) and polymer (P80) AR-type lowers. Polymer lowers are easier to complete, and provide good practice for first-time users.

Optional Bits

• (1) ⅜ Drill Bit - 5”
• (1) 5/32 Drill Bit - 3”
• (1) ⅜ Short End Mill - 3”
• (1) 5/16 Short End Mill - 4”
• (1) ⅜ Long End Mill - 4”

These bits are optional, but highly recommended. They're designed to complete both types of 80% lowers.Together, the bits and Elite Builder Jig are capable of fabricating multiple lower receivers before tooling needs to be replaced. Replacement plates and bits are available, should any wear or damage occur while you work.

Liberty 80% Lower (AR-15, AR9)

The Liberty AR Jig is basically a cheaper, simpler version of the Elite Builder Jig. It uses the same basic design -- side plates with drill guides, and top plates with milling guides -- to fabricate an AR-15 or AR9 lower. Unlike the EB Patriot, though, it cannot physically accommodate larger .308 lowers.

Optional Bits

• (1) ⅜ Drill Bit - 5”
• (1) 5/32 Drill Bit - 3”
• (1) ⅜ Short End Mill - 3”
• (1) 5/16 Short End Mill - 4”
• (1) ⅜ Long End Mill - 4”

The optional bits available for the Liberty Jig are the same as the Elite Builder Jig.

Broken Arms Jig (AR-15, AR9)

The Broken Arms Jig provides perhaps the best performance when used with a tabletop drill press. Its multiple drilling templates provide extra removal of the aluminum in the fire control cavity, before milling is required. This makes the entire fabrication process easier and faster. Its only drawback is its lack of compatibility with .308 receivers -- which, at this time, only the Elite Builder Jig provides.

Included Bits

In addition to the convention 3/8" drill bits and necessary 5/16 and other end mills, the Broken Arms Jig includes smaller drill bits. These additional drill bits are intended to be used with the extra fire control cavity guides, before stepping up to the end mill bits.

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80% Pistol Jig Compatibility

Currently, jigs are available for the GLOCK and 1911 handgun platforms and their respective 80% frames.

80% Glock Jig

At this time, the Polymer80 Handgun Frame Jig is discontinued at this time. The P80 Jig is designed to guide the drilling and trimming steps required to fabricate a Polymer80 ("P80") pistol frame. 

Stealth Arms "Phantom" 1911 Jig

Although the original 1911's frame is steel, forged aluminum 80% frames now exist for the built-it-yourself market. These frames are manufactured by Stealth Arms, who also produces the requisite 1911 Phantom Jig. Like an AR-type jig, the Phantom Jig utilizes standard high-speed steel drill bits for completing the 1911's pin holes.

Instead of using end mill bits with a mill or drill press, the 1911 frame is cut by hand, using a cutting plane, similar to a wood planer. The hand plane incorporates a hardened steel blade that shaves down the frame for proper slide and barrel installation.

Ready to build? Here's how to complete an 80% lower.

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Frequent Jig Questions

Q: What jig do I need to complete a 300 BLK lower?

A: A 300 Blackout-chambered lower is merely a 5.56/.223 lower receiver. The only difference between a 300 BLK and 5.56/223 AR-15 is the barrel and gas system length.

Q: What jig works with 9mm AR lowers?

A: Any jig that works with standard 5.56/.223 lowers also works with the available 9mm (AR9) 80% lowers currently on the market.

Q: Do any jigs come with an 80% lower?

A: No. Because of recent ATF decision-making, 80% lowers and 80% frames are sold separately from jigs and tooling.

Q: Are Polymer80 frames still available with their jigs?

A: At this time, P80 frame-and-jig combos have been discontinued and are not available through us, nor through Polymer80 directly.

Q: What tools do I need to use my jig?

A: All AR-type jigs we sell are designed to function with a standard drill press. For drilling the pin holes in a GLOCK or 1911 frame, those jigs can also be used with a drill press. For GLOCK jigs, a Dremel can be used for cutting the frame. The 1911 jig includes a cutting implement.

This guide compares the types of tools that can be used with an 80% jig.

Q: Are jigs considered firearms?

A: No. As much as the ATF would like to claim otherwise, 80% jigs are not firearms. They aren't gun parts, either. They are tools. 

However, some states have banned these types of tools and products. Always check your local and state laws before attempting to buy firearm parts. We list which states wherein we cannot sell nor ship our products on our Shipping & Returns Page.