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Tool / AR-15 / Configurator
AR-15 parts laid out on a workbench
Free Online ToolAR-15
Tool / AR-15 / Configurator

AR Builder: Configure Your Custom AR-15 Online

Free online tool for designing custom AR-15s with real-time compatibility checking, live budget tracking, and capability analysis across 14 part categories. Pick from 60+ factory platforms or build a custom AR-15 from individual upper, barrel, handguard, BCG, and control parts.

Launch AR BuilderBrowse Build Templates
Feature Set
06 / 06
Most AR builders stop at a parts list. This one checks every component against your platform, scores your build across eight mission profiles, and keeps a running budget so you know what you are actually buying before you open a tab at Optics Planet.

Full Parts Coverage

10 AR-specific core slots (upper, lower, barrel, handguard, BCG, charging handle, trigger, grip, stock, safety selector) plus 14 accessory categories including optics, magnifiers, weapon lights, lasers, muzzle devices, suppressors, BUIS, and slings.

Real-Time Compatibility

Every component is tag-matched against your platform for rail type, barrel length, caliber, and mounting interface. Incompatible parts are filtered out automatically before you select them.

Capability Radar

Your build is scored live across eight axes: CQB, long range, low light, night vision, suppression, mobility, reliability, and modularity. Shift components and watch the chart update.

Budget Tracking

Running totals with current vendor pricing. Set a ceiling, see what each category costs, and spot the parts eating your budget before you buy anything.

Save, Share, Export

Saves to your browser on one tap. Sign in with Google to sync across devices. Every build generates a shareable URL, plus CSV, PDF, and QR export for offline reference.

No Account Required

The full AR builder runs in your browser for free. Sign-in is optional and only needed for cross-device sync or saving multiple builds long-term.

How It Works
03 STEPS
01

Pick a platform, or go fully custom

Start from 60+ factory AR-pattern rifles: Daniel Defense DDM4V7, Knights Armament SR-15, LMT MARS-L, BCM RECCE, Aero M4E1, PSA PA-15, and more. Or select Custom AR-15 to assemble from individual parts: upper receiver, barrel, handguard, BCG, charging handle, trigger, grip, safety selector, and stock.

02

Layer accessories across 14 categories

Walk through optics, magnifiers, lights, lasers, suppressors, muzzle devices, BUIS, slings, and grips. Compatibility filters run in real time, so if your platform has a 10.3" barrel, long-range glass and rifle-length gas parts disappear from the options.

03

Review, budget, and export

The review step shows your capability scores, budget totals, and every component with current vendor links. Save to the browser, generate a shareable URL, or export CSV, PDF, and a QR code for the range bag.

Start Your BuildBrowse the Catalog
Starter Builds
06 TEMPLATES
Every card below deep-links into the AR builder with every component pre-selected. Open one, swap parts to match your budget or use case, and export. You never start from a blank page.

Entry-Level AR-15 Builds

Budget-conscious builds that still run hard. Start here if it is your first rifle or first aftermarket upgrade path.

cqb$1,200 - $1,800

Budget CQB

Effective close quarters without breaking the bank

PSA PA-15 16" CarbineBeginner
  • Compact 16" platform for maneuverability
  • Red dot optic for fast acquisition
Open in Builder
versatile$2,400 - $3,600

All-Around Duty

Jack of all trades, master of versatility

BCM RECCE-16 MCMRIntermediate
  • 16" barrel balances velocity and handling
  • LPVO for near to mid-range work
Open in Builder
lightweight$2,000 - $3,200

Lightweight Recce

Go further with less fatigue

KE Arms WWSD 16"Intermediate
  • Lightweight components throughout
  • Minimalist accessory selection
Open in Builder

Advanced AR-15 Builds

Mission-specific configurations: precision, suppressed home defense, and night-vision positive-identification rifles.

precision$2,800 - $4,200

Precision DMR

Reach out and touch targets at distance

Aero Precision M4E1 Complete Rifle 16"Intermediate
  • 18" or longer barrel for velocity
  • 1-6x or 1-8x LPVO for versatility
Open in Builder
suppressed$3,200 - $4,800

Suppressed Home Defense

Hearing-safe home protection

BCM RECCE-11 MCMRIntermediate
  • Suppressor for hearing protection
  • Compact platform for indoor use
Open in Builder
night-vision$4,500 - $7,000

Night Vision PID

See and identify in complete darkness

Daniel Defense DDM4 V7Advanced
  • IR laser/illuminator for aiming under NV
  • Suppressor-ready for reduced signature
Open in Builder
Choose Your Path
CUSTOM VS FACTORY
The AR builder supports both approaches. Pick the one that matches your experience, budget, and timeline.

Build custom

Choose when you want a specific trigger, barrel profile, or gas system that no factory rifle ships with. Good for Form 1 SBR builds, pin-and-weld muzzle devices, non-standard calibers like 300 Blackout or .224 Valkyrie, and for learning the platform by assembling it yourself. Use the Custom AR-15 path to pick upper, barrel, handguard, BCG, charging handle, grip, trigger, stock, and safety selector individually.

Start with a factory platform

Choose when you want a known-good spec, a single warranty, and faster time to range. The catalog includes 60+ AR-pattern platforms spanning Daniel Defense, Knights Armament, LMT, BCM, Aero, and PSA, plus piston guns from LWRC and POF. Compatibility still runs on every accessory, so you cannot bolt an M-LOK light to a KeyMod handguard by mistake. Browse the platform catalog to compare specs before picking.

Keep Reading
RELATED INTEL

Before committing to a barrel length, read the AR-15 barrel length guide to see why 11.5 to 16 inch barrels dominate and where the tradeoffs live. If you are choosing ammunition, the 5.56 ammo selection guide breaks down M193, M855, Mk262, and match loads with real terminal and accuracy data. New to the platform entirely? Start with build your first AR, which walks through the ten core parts the custom path in this AR builder asks you to choose.

Optics are usually the biggest single line item. The optic selection matrix matches red dots, LPVOs, prisms, and magnified scopes to barrel length, mission, and budget. For anything short-barreled or subsonic, the 300 Blackout guide covers platform setup, ammunition, and why the caliber exists. Already have an idea and want a second opinion? Run the firearm skills quiz or use the platform comparison tool to put two rifles side by side.

AR Builder FAQ

▶Is there a free AR builder website?
Rifle Configurator is a free online AR builder that runs in your browser with no account required. It covers custom AR-15 builds from individual parts (upper, barrel, handguard, BCG, charging handle, trigger, grip, stock, safety selector) and 60+ factory AR-pattern platforms. The builder runs real-time compatibility checks, tracks budget with live vendor pricing, and scores each configuration across eight capability axes including CQB, long range, low light, suppression, and mobility. Sign-in is optional and only needed to sync builds across devices.
▶How does the AR-15 builder work?
Start by picking a factory platform (Daniel Defense DDM4V7, Knights Armament SR-15, LMT MARS-L, BCM RECCE, PSA PA-15) or select Custom AR-15 to choose individual core parts. The builder walks you through 14 accessory categories: optics, magnifiers, weapon lights, lasers, suppressors, muzzle devices, BUIS, slings, and more. Every component is checked against your platform for compatibility based on rail type (Picatinny, M-LOK, KeyMod), barrel length tier (ultra-compact, compact, standard, long), caliber, and mounting interface. A capability radar chart updates in real time, and budget tracking shows running totals with current vendor pricing.
▶Can I build a custom AR-15 from individual parts in this configurator?
Yes. Select Custom AR-15 on the platform step and the AR builder switches into a core-parts flow before accessories. You pick the upper receiver (stripped or complete), lower receiver, barrel, handguard, BCG, charging handle, trigger, grip, stock, and safety selector one at a time. A complete-upper shortcut lets you set upper, barrel, and handguard in a single selection if you are sourcing a factory upper. After core parts lock in, the same 14 accessory categories layer on top with compatibility checks preventing mismatched parts (for example, a .223 Wylde barrel blocks .308 handguards from ever appearing).
▶What parts does the AR builder cover?
14 component categories plus 10 AR-specific core slots. Core: upper receiver, lower receiver, barrel, handguard, BCG, charging handle, trigger, grip, stock, safety selector. Accessories: magnified optics (LPVO, prism, variable), red dots, magnifiers, weapon lights, lasers and IR illuminators, muzzle devices (brakes, comps, flash hiders, linear comps), suppressors, backup iron sights, slings, vertical grips, angled foregrips, and bipods. The catalog covers budget tiers (PSA, Magpul) through mid-value (Aero, Geissele) to premium (Daniel Defense, Knights Armament, LMT, Surefire, Trijicon, Nightforce).
▶Can I save and share my AR-15 builds?
Yes. Builds save to your browser automatically with one tap. Sign in with Google to sync across devices and keep multiple named builds. Every build generates a shareable URL you can send to friends, post in forums, or share on social media. The review step also supports CSV export, PDF export, and a QR code for quick mobile sharing. When someone opens your shared URL, the builder pre-loads the exact platform and components so they can fork the build or price it themselves.
▶Is it legal to build your own AR-15?
Under federal law (Gun Control Act of 1968), it is legal to manufacture a firearm for personal use without a license in most circumstances. You do not need a serial number for a personally manufactured firearm that you do not intend to sell. However, state and local laws vary significantly. Some states restrict or ban home-built firearms, unserialized receivers, or specific configurations. Barrels under 16 inches on a rifle require an NFA tax stamp (Form 1 SBR) unless the firearm is configured as a pistol with a stabilizing brace. Always verify your state and local regulations before starting a build. This is general information, not legal advice.
▶Do I need an FFL to use this AR builder?
No. The AR builder is a free planning and research tool, not a parts retailer. You use it to verify compatibility, compare specs, plan your budget, and share build ideas. When you are ready to buy, each component links out to vendors like Optics Planet, Primary Arms, and Brownells with current pricing. Only the stripped or complete lower receiver (the serialized part of an AR-15) requires an FFL transfer when you actually purchase it. Accessories, barrels, handguards, BCGs, triggers, optics, and most other parts ship directly to your door.
▶What is the best AR-15 configuration for home defense?
A home defense AR-15 runs an 11.5 to 14.5 inch barrel, a reliable red dot (Aimpoint PRO, Holosun 510C, EOTech EXPS3), a weapon light rated 500+ lumens with white-light throw (Surefire M600DF, Streamlight ProTac Rail Mount HL-X), a two-stage trigger that breaks under 5 lb (LaRue MBT-2S, Geissele SSA-E), and a suppressor if your state allows (SilencerCo Omega 36M, Dead Air Sandman-S). Shorter barrels run a pistol-length gas system and tend to over-gas without a tuneable gas block. Use the Suppressed Home Defense or Budget CQB templates in the AR builder to start from a vetted baseline, then adjust components to your budget and legal environment.
Ready / Launch Sequence

Ready to build your AR-15?

Free, browser-based, no account required. Fork a starter build or start with a blank custom AR-15.

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