Cast Mold Your Own AR Lower Receiver

Nathan S
by Nathan S

80% lowers are all the rage for the do-it-yourself types or those wanting to avoid the prying eyes of the US Government. The lowers are effective, but always require a machine to be able to finish (including the polymer lower receivers). Out to change that requirement and lower the barrier to entry to non-technical folk is, which has created a home casting kit for their polymer receivers.

The base kit retails for $329.99 which includes enough material to manufacture 5 lower receivers. It includes:

  • The base reusable mold halves
  • The small parts kits (inserts)
  • Mag hold block
  • Fire control group mold block.
  • Nuts & bolts
  • Polymer Resin

The receivers can be customized to a myriad of colors including black, blue, brown, red, orange, green, violet, & yellow. Conceivably, one could do any color with various combinations of the dyes. Additional resin mold material is about $119 for 5 additional receivers. Colors can likewise be purchased as a kit or individually.

To ensure long-term usability, the receiver has some of the usual reinforcements found on other polymer receivers. The buffer tube tower is reinforced, the trigger guard is integral, and base receiver has struts.

For those interested in the kit, check out their website and some videos below on how to use the kit with its various inserts.

Nathan S
Nathan S

One of TFB's resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR's, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.The above post is my opinion and does not reflect the views of any company or organization.

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5 of 28 comments
  • Chadd Chadd on Feb 08, 2016

    This seems like it would be fantastic for a pistol caliber lower. But knowing what I do about FRPs, I wouldn't trust just straight resin with anything that had too much recoil.

  • Jerry young Jerry young on Feb 09, 2016

    I've never been around a polymer AR and am not sure I even want to, I just see to much going wrong with a plastic AR

    • See 2 previous
    • Cymond Cymond on Feb 12, 2016

      @jerry young Pin-hole wear is probably an issue as well. There's definitely a lot more potential for wear, but that would be over a life of many, many thousands of rounds. Many would consider that a fair trade for lighter weight and lower cost.

      As for flexing, polymer has a great reputation for taking that kind of stress/abuse and returning to normal. In some cases, certain polymer receivers have survived trauma that has destroyed aluminum AR-15s. Unless you're trying to build a longe range precision rifle, the flex in a polymer AR receiver is a non issue.

      Fwiw, I really like the feeling of an all-steel handgun, too. I had a full size 9mm 1911 that was a sweet shooter.

      Maybe I misunderstood you. Your phrase "I've never been around a polymer AR and am not sure I even want to" sounded like you were afraid of them for safety reasons.