Luth-AR Builder Lower Parts Kit for AR15 - No Grip / Fire Control Group

Manufactured by Luth-AR
Manufactured by Luth-AR
7 Reviews

In Stock

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Luth-AR LLC, known for the lightest and most affordable adjustable buttstocks, bring you innovative and exciting AR parts and accessories, all made in the U.S.A.

The Luth-AR Lower Receiver Parts AR-15 Builder Kit is a great foundation for your stripped lower receiver. For armorer’s starting a build where a drop-in trigger and custom grip are planned, this kit is the perfect choice. It includes all the required small parts to get your build started, less the custom parts you won’t need from an LPK. This MIL-SPEC kit is compatible with virtually all AR-15 lower receivers on the market.

NOTE: Grip and fire control group are not included.

Kit Includes:
  • Buffer retainer
  • Buffer retainer spring
  • Safety selector
  • Selector spring
  • Safety detent
  • Bolt catch spring
  • Bolt catch plunger
  • Bolt catch
  • Bolt catch roll pin
  • Pivot pin
  • Takedown pin
  • (2) detent springs
  • (2) takedown/pivot detents
  • Magazine catch
  • Mag catch spring
  • Aluminum magazine catch button
  • (2) hammer/trigger pins
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California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to

Ratings & Reviews

7 reviews


Magazine Catch is serviceable but has issues


Most of the parts are perfectly fine with no quirks, but the magazine catch is not quite right, the way it is cast lets numerous brands of magazine be pulled out of the magwell when they should be locked in, (namely Mission First, C Products, and various oddball GI mags though other GI mags work just fine). This was not a fluke with 1 kit as I have used 2 of these and they both had this issue. I replaced the catches with different ones and the problem was immediately fixed in both guns. Also, Magpul magazines will not seat while loaded with this kit's magazine catch.

Worked for me

by -

Took a chance and grabbed one of these while on sale. Everything went together nicely and functions perfectly. No complaints


by -

Safety is junk. I tried it in another lower I had and it was the same. I tried to polish the journals. It got better but I could see there uneven parts. Polished more and then it rotated in the lower without issue. When I installed the detent it got rough again. So I took a fine wire wheel in my Dremel. Polished it the best I could but it was still rough. You could see the detent was getting worn also. I thought all LPK’s were the same with in reason. Guess I was wrong

Safety selector out of spec

by -

All parts fit fine into an Anderson stripped lower except for the safety selector. Luckily I had a spare dpms selector that went right in, so I know that it wasn't the lower receiver that was out of spec.

Poor Finish On Parts, NFG.

by -

Finish on parts is cheap. Scratches occurred on pivot pin and other parts during install. I’ve never had the above mentioned issue with Aero or KAK parts. Safety sucks and is not smooth. Packaging is top notch however, priorities!!! I would not purchase this kit again no matter the price.

Serviceable Kit


I ordered this Parts Kit in May of 2019 and assembled my Anderson Lower with it. I have built around 10 other lowers with kits from different manufacturers. I had no issues with this Luth kit and the it looked acceptable. Probably 400 rounds on the lower and still going strong.


by -

All parts fit well except for the rear takedown pin. It was round & would not close all the way down. Had to use a grinder on it to make the side facing the buttstock flat so the pin would go all the way in. This was on an Anderson lower.