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Polymer80 RJ556U – Universal 80 Lower Jig for Mil-spec AR-15/AR9 80% Lower Receivers


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SKU: P80-RJ556U Categories: ,


This jig is compatible with our Forged 80% Lowers. Our Premium Fire/Safe Marked Billet 80% Lowers are not compatible with this 80% lower jig. Other manufacturer’s billet 80% lowers may compatible with this 80% lower jig, provided their lower receiver design adheres to mil-spec specifications.

Looking for the perfect affordable alternative to the expensive and more complicated metal jigs? You’ve come to the right place! This low-cost 80 lower jig by Polymer80 is a perfect choice, especially if you’re just planning on finishing a few AR15 or AR9 80 lowers. Why pay more, right?

The Polymer80 RJ556U AR15/AR9 Universal Jig is an excellent addition to the very popular Polymer80 line. This Polymer80 jig wasn’t only designed for polymer lowers in mind. This 80 lower jig was created for compatibility with all mil-spec 80% AR15 lower receivers and AR9 80 lowers, whether they are polymer OR metal. The Polymer80 AR15 Universal Jig is designed with a super rigid long-fiber nylon composite, which will allow you to utilize the 80% lower jig up to 3 times.

The  Polymer80 RJ556U AR15/AR9 Universal Jig is designed to provide a stable platform for milling, and therefore encompasses the entire AR15 or AR9 lower receiver. Other competing 80 lower jigs are typically more expensive and difficult to secure the 80 lower in the vise and more likely to damage the 80 lower receiver while milling.

The Polymer80 P80RJ556U AR15/AR9 Universal Jig includes:

  • 2 sided jig
  • 3 trigger guides
  • 9mm HSS end mill
  • 5/16ths drill bit
  • 3/8ths drill bit
  • 5/32nd drill bit

Example Tools Needed:

Extremely expensive or high-end tools are not required to use this jig to finish your lower.  All of the suggested tools mentioned below can be utilized for other popular Polymer80 receiver projects, including .308 80 lower receivers and 80% Glock® compatible pistol frames, so it’s easy to justify the expense!

  • Vise For Drill Press – 6” inch jaws
  • Drill Press -1850-2250 RPM
  • Digital Calipers
  • Dremel Bit #9904
  • Level
  • Round Machinists File
  • Non-marring vice jaws
  • Lower Receiver Vice Block
  • Upper Receiver Vice Block

The complete list of suggested tools can also be found in the instruction guide

What are you waiting for?  Your build awaits!


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