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JMT AR-15 Gen 2 80% Polymer Lower with Jig and Mil-Spec AR15 Lower Parts Kit - Black

Was: $134.99
Now: $124.99
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Back in the era of infomercials, you used to hear talk of things being made from "space-age polymer." Well, it's more normal now than space-age, but polymer is definitely still something to talk about, especially in the gun industry. In the case of your next AR build, use a polymer 80% lower receiver for the several benefits it affords you. Polymer is lighter, easier to cut into and mill out, and just as tough as mil-spec aluminum lowers. We want to get you started with your next AR build, not only by giving you James Madison Tactical's Gen 2 polymer 80% lower with the necessary jig, but we also included a mil-spec lower parts kit in the package too.

The JMT AR-15 Gen 2 80% Polymer Lower with Jig

Want the toughest, lightest, and most affordable 80% lower? Check out JMT’s new Gen 2 Polymer 80% Lower. It includes the required 80% jig for cutting the fire control cavity and drilling the holes for your hammer, safety, and safety lever. 

High-Strength, Reinforced Polmyer

Even though this is a steal, this lower’s not a gimmick: JMT massively reinforced this lower with plenty of upgrades to ensure it can handle all the 5.56, .223 and 300 BLK rounds you throw down the muzzle. They even took their existing polymer-fiber material and made it tougher, stiffer, and stronger. It can handle high heat, rapid fire, and high impacts.

Mil-Spec Compatibility

This 80% lower’s mil-spec with all fittings and threads and is 100% compatible with any standard AR-15 LPK, buffer tube or pistol brace, upper assembly, and magazine on the market.

Upgraded Features:

  • Extended upper fire control box sections.
  • Upper left magazine well box section.
  • Webbed magazine wells match Magpul mags.
  • Extended bolt release roll pin posts.
  • New JMT Gen2 logo markings.

Manufacturer instructions can be found here.

No FFL is required to purchase this lower receiver. This polymer 80% lower receiver is not considered a firearm and is compliant with ATF receiver blank determinations (Gun Control Act of 1968). Not classified as a firearm as defined in 18 U.S.C. 921(a)(3).

The Mil-Spec AR-15 Lower Parts Kit

This AR-15 Lower Parts Kit includes all components required for assembling your AR-15 stripped lower receiver:

  • Bolt Catch
  • Bolt Catch Plunger
  • Bolt Catch Roll Pin
  • Bolt Catch Spring
  • Buffer Retainer
  • Buffer Retainer Spring
  • Disconnector
  • Disconnect Spring
  • Steel Hammer
  • Hammer Pin
  • Hammer Spring
  • Magazine Catch
  • Magazine Catch Button
  • Magazine Catch Spring
  • Pistol Grip (A2 style)
  • Pistol Grip Lock Washer
  • Pistol Grip Screw
  • Pivot Pin
  • Pivot Pin Detent
  • Pivot Pin Detent Spring
  • Selector
  • Selector Detent
  • Selector Detent Spring
  • Takedown Pin
  • Takedown Pin Detent
  • Takedown Pin
  • Detent Spring
  • Steel Trigger
  • Trigger Guard
  • Trigger Guard Roll Pin
  • Trigger Pin
  • Trigger Spring

WARNING: Handling firearms parts and accessories can expose you to lead and other petroleum products known to the State of California to cause cancer and reproductive harm. For more information go to:

Shipping Restrictions

Shipping of various parts and/or accessories are prohibited to states and locales (ie New Jersey, California, New York, etc…) with restrictions against certain parts and/or accessories or "assault weapons" (i.e. states with high-capacity magazine restrictions, manufacturing of semi-automatic weapons, etc..). It is your responsibility to be aware of your local firearms laws before purchasing from our website or machining a firearm. We try our best to keep our shipping page current, but laws change daily. only ships within the United States. Federal legislation dictates we cannot ship our products internationally.

Polymer Composite
.223 Wylde
.300 AAC Blackout
6.5 Grendel
James Madison Tactical

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.