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AR-15 Lower Parts Kits, LPKs & Complete Build Kits

Finish the lower in one order. AllGoOperators stocks the USA-made AR-15 Lower Parts Kit at $49.99, the B5 Systems LPK rifle build kit, the CAR-15 retro build kit in ODG, and upper-plus-lower build kits in 5.56 and 7.62x39 that pair a complete upper with every lower part except the stripped receiver.

Shop By Build Stage

Every Lower Kit, Sorted

From a bag of springs and pins to a complete rifle minus the stripped lower.

01

Standard Lower Parts Kit

The AR-15 Lower Parts Kit is made in the USA and includes trigger, hammer, disconnector, springs, pins, detents, magazine catch, bolt catch, takedown and pivot pins, selector and an aluminum trigger guard. Everything for a working lower minus the pistol grip.

AR-15 Lower Parts Kit Pistol Grips Safety Selectors
02

Premium & Retro Kits

The B5 Systems LPK rifle build kit adds B5 furniture, and the CAR-15 Retro Build Kit in ODG gives a Vietnam-era carbine look with a matching lower parts kit.

B5 Systems LPK Build Kit CAR-15 Retro Build Kit ODG A2 Stock Kit FDE
03

Upper + Lower Build Kits

Skip the parts list. Each build kit bundles a complete upper (16" or pistol length, in 5.56 or 7.62x39) with a lower parts kit, buffer kit and stock. Add a stripped lower and you have a rifle.

16" 5.56 Build Kit 5.56 Pistol Build Kit 16" 7.62x39 Build Kit 7.62x39 Pistol Build Kit All Build Kits
04

Trigger & Buffer Upgrades

Swap the mil-spec trigger in the kit for a Super Safety or forced reset trigger, and run the HFRT heavy buffer kit to support it.

AR-15 Triggers HFRT Heavy Buffer Kit Buffer Kits & Parts Anti-Walk Pins
LPK Anatomy

What Is In the Kit

Our standard lower parts kit, part by part.

Fire Control

Trigger Group

  • Trigger & hammer Mil-spec steel with springs.
  • Disconnector & spring Catches the hammer between shots.
  • Hammer & trigger pins Two standard .154 pins.
  • Safety selector Single-side lever, spring and detent.
  • Trigger guard Aluminum, black, with roll pin.
Receiver Parts

Controls & Pins

  • Magazine catch Catch, button and spring.
  • Bolt catch Catch, plunger, spring and roll pin.
  • Takedown & pivot pins Pins with two sets of detents and springs.
  • Buffer retainer Detent plunger and spring for the buffer tube.
  • Not included Pistol grip, buffer tube, buffer, spring and stock.
Before You Order

Choosing a Lower Parts Kit

What you already have decides which kit you need.

Stripped Lower Only

Order the standard LPK, a pistol grip, a buffer tube kit and a stock, or choose a complete upper-plus-lower build kit and add nothing but the receiver.

Replacing a Trigger

If you are upgrading to a Super Safety or drop-in FRT, the standard LPK still supplies every other small part. Set the mil-spec trigger and hammer aside as spares.

Caliber

The 5.56 and 7.62x39 build kits differ in upper only. The lower parts kit, buffer and stock are the same for both.

Lost Detent

The single most common reason to buy an LPK is a launched detent or spring. The kit includes two sets of takedown and pivot detents.

Frequently Asked Questions

  • What is included in the AR-15 lower parts kit?

    Trigger, hammer, disconnector and springs, hammer and trigger pins, single safety selector with spring and detent, magazine catch assembly, bolt catch assembly, takedown and pivot pins with two sets of detents and springs, buffer retainer and spring, and an aluminum trigger guard. Made in the USA. The pistol grip is not included.

  • Is a pistol grip included?

    No. The standard LPK is sold without a grip so you can choose your own. Rubberized and storage grips are in our pistol grips category.

  • What is an upper-plus-lower build kit?

    A complete upper receiver bundled with a lower parts kit, buffer kit and stock. Add a stripped lower receiver, which ships to an FFL, and you have a complete rifle or pistol.

  • Can I use this LPK with a forced reset trigger?

    Yes. Install the Super Safety or drop-in FRT in place of the kit's trigger and hammer and use the rest of the kit as normal. Add anti-walk pins and a heavy buffer.

  • Does the LPK fit an AR-9 or AR-10?

    AR-9 lowers use this kit. AR-10 lowers need the AR-10 LPK with 308-pattern bolt catch, takedown and pivot pins.

  • Do lower parts kits require an FFL?

    No. Lower parts kits and build kits ship directly to you. Only the stripped lower receiver itself is a firearm and must ship to an FFL. Complete uppers in the build kits require an FFL address for CA, WA, CT, NJ, New York City and Chicago.

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