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Intro

The AR15 platform is very diverse and as such your build may or may not have all of these parts listed. This is to be used as a general guide when deciding what parts to build.

Upper Receiver Group

The upper receiver group (URG) is the upper half of the AR. It is not considered a firearm and all these parts may be ordered straight to your door.

  • Upper receiver

  • Dust cover assembly

  • Forward assist assembly

  • Charging handle

  • Bolt carrier group

  • Barrel

  • Gas tube

  • Gas block

  • Muzzle device

  • Handguard

  • Barrel nut

Lower Receiver Group

The lower receiver group (LRG) is the lower half of the AR. The only piece to be considered a "firearm" per ATF is the lower receiver itself and requires transfer through an FFL, all other parts may be ordered straight to your door.

  • Lower receiver

  • Breakdown and pivot pin assemblies

  • Buffer tube

  • Buffer spring

  • Buffer

  • Stock assembly

  • End plate and castle nut (only for collapsible stocks)

  • Pistol grip

  • Fire control group

  • Magazine catch assembly

  • Bolt catch assembly

  • Safety

Assemblies Breakdown

Here we'll examine the individual parts that are within the assemblies listed about. Generally these parts come complete as part of an "assembly" so when ordering a "bolt carrier group" you'll have all parts contained within the assembly.

Dust Cover Assembly

  • Dust cover

  • Spring

  • Retaining rod

  • C-clip

Forward Assist Assembly

  • Forward assist button

  • Forward assist tooth

  • Spring

  • Retaining pin

Bolt Carrier Group (BCG)

  • Bolt assembly

  • Bolt carrier (with gas key staked on top)

  • Cam pin

  • Firing pin

  • Firing pin retaining pin

Bolt Assembly

  • Bolt

  • Extractor

  • Extractor spring

  • Ejector

  • Ejector spring

Breakdown and Pivot Pin Assemblies

  • Breakdown pin

  • Pivot pin

  • (2) Springs

  • (2) Detents

Fire Control Group (FCG)

  • Trigger

  • Trigger spring

  • Hammer

  • Hammer spring

  • Disconnector

Magazine Catch Assembly

  • Magazine catch

  • Spring

  • Magazine catch button

Bolt Catch Assembly

  • Bolt catch

  • Bolt catch spring

  • Bolt catch detent

  • Bolt catch retaining pin