New KP-15 Polymer Lower Receiver For AR-15 Rifles From KE Arms

Doug E
by Doug E
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For those of you following the “ What Would Stoner Do” (WWSD) series on the InRangeTV YouTube channel, you know that a monolithic polymer AR-15 Lower receiver is in the works. This polymer lower is being produced by KE Arms, and they’ve dubbed the new AR component as the KP-15. It features an A1 length stock and will come in four different configurations in regards to the internal parts. The KP-15 has been in development for some time, but for those eagerly waiting, the product seems nearer at hand as Brownells has now listed it for sale on their website, and KE Arms states that they’re planning to fill Brownells’ order first. KE Arms’ product description can be found below:

The KP-15 is a monolithic polymer AR15 style receiver made from injection molded 30% glass filled nylon incorporating the buttstock, buffer tube, pistol grip, and trigger into the receiver design as integral components.

This manufacturing process offers several advantages

  • Lighter weight compared to similarly configured receivers
  • Lower cost to similarly configured receivers
  • Increased production speed and elimination of sub components through integration; especially important during high demand cycles in the market.

Features Include:

  • Compatibility with most common AR15 uppers and lower parts kits
  • Flared magwell to make reloads under stress easier to perform.
  • A1 Length 13” Length of Pull (LOP) Buttstock to fit a wide range of shooters
  • MLOK Slots at rear of stock for sling attachement points or run a strap through it for simple sling attachment
  • Holes at the front of the stock for QD socket inserts for more sling attachment options
  • Improved grip for comfortable use
  • “Winter” Trigger Guard

Technical Information

  • The KP-15 receiver uses a Carbine buffer and spring
  • The Take Down and Pivot Pins have the detents built into them; eliminating the spring and detent holes in the lower increases durability.
  • The buffer detent (should you choose to use it) is held in place with a 5/64” Roll Pin
  • The KP-15 is compatible with all Mil-Spec Fire Control Groups
  • The KP-15 is compatible with cassette style match triggers including the KE Arms DMR and SLT units. The retention system of these triggers with D-Clips in the bushings to retain the fire control pins makes them better suited for use in the KP-15 than other designs that require captured pins.
  • The hammer pin area is wider for durability; Standard AR15 hammer pins can still be used but we offer a longer hammer pin for customers preferring a flush pin for aesthetic reasons.
  • Safety selector spring and detent load from the top and then the selector is slid over them.  Standard selectors can work but removing them can be particularly difficult.   We recommend the use of our optimized mil-spec selector or optimized ambi selector to make removal easier.  Follow our assembly guide for further instructions.
  • The KP-15 is compatible with standard AR15 uppers in calibers including .223/5.56mm NATO, .300 Blackout, 6.5mm Grendel, 6.8mm SPC; make sure you use the appropriate weight carbine buffer for your rifle to eject at 3:00-4:00.
  • The KP-15 is compatible with 9mm blowback systems with a 5.4oz carbine buffer minimum.  Use heavier buffers as long as your gun can cycle reliably.  Failure to use this minimum buffer weight can damage the lower.
  • Big Bores: .458 SOCOM, .50 Beowulf, .50 BMG: We will never test these calibers enough to guarantee function and durability over time; use at your own risk.”
Image credit:
KE Arms KP-15 Lower receiver. Image credit:
Image credit: Brownells

Brownells’ YouTube channel gives a great look at the KP-15 Lower receiver as they introduce the new catalog listing:

Brownells has published their own article that follows the development of the KP-15 polymer receiver, and also includes more videos from InRangeTV. The following links are to each of the four configurations Brownells is offering.

KP-15 Complete Lower with Ambi Controls $499.99

KP-15 Lower with DMR trigger $299.99

KP-15 Complete Lower, Mil-Spec $199.99

KP-15 Stripped Lower, $109.99

You can find out more about the KP-15 from KE Arms on the dedicated webpage, or view their full product line on their main website. You can also follow them on Facebook and Instagram.

What do you think about the new KP-15 polymer Lower receiver from KE Arms? Have you been following the WWSD series? Either way, tell us what you think in the comments section!

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Doug E
Doug E

Doug has been a firearms enthusiast since age 16 after getting to shoot with a friend. Since then he's taken many others out to the range for their first time. He is a husband, father, grandfather, police officer, outdoorsman, artist and a student of history. Doug has been a TFB reader from the start and is happy to be a contributor of content. Doug can be reached at battleshipgrey61 AT, or battleshipgrey61 on Instagram.

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3 of 117 comments
  • Mazkact Mazkact on Dec 10, 2020

    I wonder how a carbine buffer system would "act" with a rifle length upper. I honestly do not know, never tried it. I do not even own a carbine length gas system, all rifle or mid length.

    • Asd Asd on Dec 10, 2020

      @mazkact all that matters is gas port size, buffer weight, spring tension, and ammo.

      you can run rifle length uppers with PDW-length buffer tubes and you can run pistol uppers with rifle-length buffer tubes as long as the gas port size, buffer weight, and spring tension are in balance for the ammo you're running.

      ARs are balancing acts to finely tune.

  • Michael Zeleny Michael Zeleny on Dec 10, 2020

    Let’s impose unit construction on a family of firearms dominating the world through modularity.

    Makes sense to me.