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

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We’re excited to introduce JMT’s new Gen 2 Polymer 80% Lower for the AR-15. This incredibly lightweight receiver blank ships with the required 80% jig to cut the trigger, hammer, and safety holes, and easily cut the fire control cavity for your LPK and trigger assembly. Ultra-light in design, the Gen 2 is guaranteed to be battle-ready.

Reinforced, High-Strength Polymer

 This 80% lower features plenty of reinforcements and upgrades to ensure it can handle any 5.56, .223, or 300 Blackout loads you slam down the upper. JMT took their polymer-fiber material and made it tough and stronger so it can withstand high heat, high impacts, and rapid fire. It’s truly battle-ready.

AR Parts compatibility

Even with a unique design and polymer construction, this receiver blank is 100% mil-spec with all fittings and threads, and is compatible with all “retail” and mil-spec AR-15 LPKs, buffers, pistol grips, and magazines.

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).

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
.300 AAC Blackout
.223 Wylde
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.