Popular Parts
Every list is ranked by real build data — the components builders on AR15.Build actually choose. Updated nightly.
Essential Components
Core components required for a complete build
Pistol Frame
Handgun frame — the serialized lower (FFL transfer required)
Frame Parts Kit
Internal frame components: connector, springs, locking block pin, mag release, and slide stop
Trigger
Fire control groups from mil-spec to precision match triggers
Lower Receiver
Stripped lower receivers requiring assembly with parts kits
Lower Parts Kit
Complete lower receiver parts kits with trigger and controls
Magazine Well Adapter
Adapts standard AR lower to accept pistol caliber magazines (Glock, Colt, MP5 patterns)
Grip
Pistol grips for ergonomics and control
Stock / brace
Buttstock assemblies and pistol stabilizing braces
Buffer Spring
Recoil springs for buffer assemblies
Buffer Tube
Extension tubes for buffer and stock assembly
Buffer
Weighted buffers for recoil management
Receiver
Stamped, milled, or cast AK receiver — the serialized component
Barrel
Rifle barrels in various lengths and profiles
Bolt Carrier Group
BCG assemblies for reliable cycling
Gas Block
Low profile and adjustable gas blocks
Gas Tube
Carbine, mid-length, and rifle gas tubes
Recoil Spring Assembly
Guide rod and recoil spring assembly
Upper Receiver
Stripped upper receivers for custom barrel and handguard builds
Charging Handle
Ambidextrous and standard charging handles
Handguard or rails
M-LOK, KeyMod, and Picatinny rail systems
Upper Parts Kit
Complete upper receiver parts and hardware kits
Pistol Slide
Complete or stripped slide assembly including rails and serrations
Slide Parts Kit
Internal slide components: firing pin, extractor, springs, and slide cover plate
Accessories & Upgrades
Optional components to enhance performance and customize your build
Magazine
High-capacity magazines and feeding devices
Slide Stop / Release
Slide stop lever and spring for Glock-compatible pistol builds
Magazine Release
Magazine catch and release button — standard, extended, and ambidextrous variants
Grip Fin
Featureless grip fin or wrap that prevents the thumb from wrapping around the grip for California-compliant builds
Stock Stop
Stock stop or limiter that converts a collapsible stock into an effectively fixed stock for California featureless compliance
Safety Selector
External safety lever — standard, short-throw, and ambidextrous variants
Bolt Catch / Release
Bolt catch, bolt stop, and bolt release lever for AR platforms
Dust Cover
AK dust cover; often upgraded for optic mounting
Muzzle Device
Flash hiders, compensators, and muzzle brakes
Suppressor
Sound suppressors and silencers for reduced report
Red Dot / Holographic Sight
1x optics for fast target acquisition at close to medium range
LPVO / Scope
Magnified optics for general-purpose, hunting, and precision builds
Magnifier
Add-on magnification for red dots and holographic sights
Bipod
Precision shooting bipod systems
Foregrip
Vertical and angled foregrips
Front Sight
Front backup iron sight
Rear Sight
Rear backup iron sight
Laser
Visible and IR laser aiming devices
Light
Tactical weapon-mounted lighting systems
Light Mount
Dedicated weapon light mounting hardware for handguards and rail systems
Pressure / Remote Switch
Remote pressure switches, tape switches, and DG switches for lights and lasers
Scope Mounts & Rings
Rings and mounts for scopes and LPVOs
Red Dot Mounts & Risers
Risers and mounts for red dots
Magnifier Mount
Dedicated mounts for magnifiers
Sling
Single and two-point sling systems