Best AR-15 Build Kits 2026: Complete Kits Ranked (PSA, Aero, BCM, Geissele) header image
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February 10, 2026

Best AR-15 Build Kits 2026: Complete Kits Ranked (PSA, Aero, BCM, Geissele)

Best AR-15 build kits ranked by tier for 2026. Complete build kits from PSA ($450), Aero Precision ($650), BCM ($950), and Geissele ($1,400) compared with lower parts kits, trigger upgrades, and kit vs individual parts cost breakdown.

BeginnerAR-15Builds

Best AR-15 Build Kits 2026: Complete Kits Ranked (PSA, Aero, BCM, Geissele)

Looking for the best AR-15 build kit? PSA is the only major brand selling actual bundled kits (upper + LPK + buffer kit + stock). For Aero Precision, BCM, and Geissele, you buy a complete upper and lower parts separately. We've ranked the best build at each tier from $450 to $1,800 with exact parts lists, total costs, and the trigger upgrade you should add to each one.

By AB|Last reviewed February 2026

What Is an AR-15 Build Kit?

An AR-15 build kit is a bundle of parts for assembling a rifle without buying a complete factory gun. The stripped lower receiver (the only serialized part) must be purchased separately through an FFL dealer with a background check.

Reality check:PSA (Palmetto State Armory) is the only major brand selling actual all-in-one build kits. Aero Precision, BCM, and Geissele sell complete uppers and lower parts as separate purchases. Most builders buy a complete upper and source lower parts individually. The term "build kit" in this guide refers to three things:

Bundled Kit (PSA only)

Upper + LPK + buffer kit + stock + grip in one SKU. PSA is the only major brand offering this. Add a stripped lower and you are done.

$450-$550

Lower Build Kit

Lower parts kit + buffer kit + stock + grip. No upper included. Buy separately when you want to mix and match tiers.

$80-$300

Lower Parts Kit Only

Just the small parts: trigger, safety, mag catch, bolt catch, springs, detents, and pins. No buffer kit, stock, or grip.

$30-$120

Best AR-15 Builds by Tier (2026)

Our Top Picks

  1. #1 PSA CHF Complete Upper ($349 upper / $550 kit): Only brand with actual kit bundles, FN CHF barrel
  2. #2 Aero M4E1 Complete Upper ($400-$550 upper): M4E1 threaded receivers, Atlas handguard, tighter tolerances
  3. #3 BCM Complete Upper ($799 upper): Conservative gas ports, instructor-recommended, professional QC

Our Top Picks

1
PSA CHF Complete Upper
Only brand with actual kit bundles, FN CHF barrel
$349 upper / $550 kit
Check Price
2
Aero M4E1 Complete Upper
M4E1 threaded receivers, Atlas handguard, tighter tolerances
$580
Check Price
3
BCM Complete Upper
Conservative gas ports, instructor-recommended, professional QC
$799 upper
Check Price
1

Palmetto State Armory PSA Complete Upper (16" CHF)

Best Budget - Only brand selling actual bundled build kits with FN CHF barrel

$349 (upper) / $450-$550 (kit bundle)
Pros
  • +FN chrome-lined cold hammer forged barrel
  • +Actual kit bundles available (upper + LPK + buffer kit + stock)
  • +Lifetime warranty
  • +Frequent sales drop kits below $400
Cons
  • −QC inconsistency reported on some batches
  • −Kit trigger is mil-spec (upgrade immediately)
  • −Fit and finish below Aero tier
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2

Aero Precision Aero Precision M4E1 Complete Upper

Best Mid-Range - M4E1 threaded receivers with Atlas handguard

$579.99
Pros
  • +M4E1 threaded upper eliminates roll pins
  • +Atlas S-ONE or R-ONE handguard included
  • +Tighter tolerances than PSA across the board
  • +Strong aftermarket support and parts availability
Cons
  • −Some uppers ship without BCG/CH (check listing)
  • −Government profile barrel adds weight
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3

Bravo Company Manufacturing BCM Complete Upper (16" ELW)

Best Duty-Grade - Conservative gas ports, excellent QC

$799 (upper) / $950-$1,200 (total build)
Pros
  • +Conservative gas ports = softer shooting, less fouling
  • +Excellent staking and quality control on every upper
  • +Gunfighter furniture is practical and durable
  • +Used by instructors and agencies
Cons
  • −Significant price jump from Aero tier
  • −Limited barrel profile options
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4

Geissele Automatics Geissele Super Duty Complete Upper

Best Premium - REBCG included in upper, pair with Geissele LPK for SSA trigger

$1,199 (upper) / $1,400-$1,800 (total build)
Pros
  • +REBCG (Reliability Enhanced Bolt Carrier Group) included in upper
  • +Geissele LPK includes SSA trigger + Super 42 buffer spring
  • +Nanoweapon coated bolt carrier
  • +Reliability Enhanced bolt and gas rings
Cons
  • −2-3x price of BCM for diminishing returns
  • −Reliability rail handguard is heavy
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View at OpticsPlanet

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Verify all parts for compliance with your local and state laws before purchasing.

Complete AR-15 Build Shopping Lists

Every part for a complete, range-ready rifle at each budget. Click any item to buy.

Budget Build

~$615 total

PSA also sells bundled kits ($450-550) with upper + LPK + buffer kit + stock in one SKU if you want fewer boxes to track.

Related Products

PSA Premium/CHF Complete Upperupper

PSA's Premium/CHF lines use FN-made barrels and solid QC for the price. Look for mid-length gas and pinned gas blocks when available.

Buy
CMMG Lower Parts Kitlower-part

Complete mil-spec lower parts kit with all pins, springs, and detents. Quality baseline for any build.

$49.99Buy
LaRue MBT-2S Triggertrigger

Precision-machined two-stage AR trigger with crisp break

$114.99Buy
Mil-Spec Buffer Tube Kitgas-component

Standard mil-spec carbine buffer tube assembly with buffer, spring, and end plate.

Buy
Magpul MOE SL Carbine Stockstock

Streamlined MOE stock with improved cheek weld

Buy
PSA Stealth Stripped Lower Receiverlower-receiver

Budget-friendly mil-spec lower with blank left side for custom engraving. Best value entry point for AR builds.

Buy

Mid-Range Build

~$845 total

Verify the Aero upper includes BCG and charging handle before ordering. "Complete" means with BCG/CH. "Assembled" means barreled only.

Related Products

Aero Precision Complete Upperupper

Clean machining, consistent gas, and easy parts support. Choose 4150 CMV or stainless barrels and pinned gas blocks when possible.

$579.99Buy
Aero Precision LPK (No Fire Control Group)lower-part

Lower parts kit without trigger group for those upgrading to aftermarket triggers. All other parts included.

$67.99Buy
LaRue MBT-2S Triggertrigger

Precision-machined two-stage AR trigger with crisp break

$114.99Buy
Mil-Spec Buffer Tube Kitgas-component

Standard mil-spec carbine buffer tube assembly with buffer, spring, and end plate.

Buy
Magpul CTR Carbine Stockstock

Compact carbine stock with friction lock and sling attachment

Buy
Aero Precision M4E1 Stripped Lower Receiverlower-receiver

Most popular upgrade lower receiver. Forged 7075-T6 with integrated trigger guard, threaded bolt catch pin, and upper tension screw.

Buy

Duty-Grade Build

~$1,114 total

The BCM upper is the heart of this build. Conservative gas ports mean softer recoil, less carbon, and longer part life.

Related Products

BCM Complete Upperupper

Conservative gas ports, excellent staking, and robust QC make BCM a reliable choice for high round counts. Opt for BFH barrels for maximum life.

Buy
CMMG Lower Parts Kitlower-part

Complete mil-spec lower parts kit with all pins, springs, and detents. Quality baseline for any build.

$49.99Buy
LaRue MBT-2S Triggertrigger

Precision-machined two-stage AR trigger with crisp break

$114.99Buy
Mil-Spec Buffer Tube Kitgas-component

Standard mil-spec carbine buffer tube assembly with buffer, spring, and end plate.

Buy
BCM Gunfighter Stock Mod 0stock

Lightweight minimalist carbine stock

$57.75Buy
BCM Lower Receiverlower-receiver

Duty-grade forged lower from BCM with enhanced features and excellent QC. Trusted by professionals.

Buy

Premium Build

~$1,574 total

The Geissele LPK ($275) includes the SSA trigger, Super 42 braided buffer spring, and all lower small parts. Buffer tube, stock, and grip are extras you pick.

Related Products

Geissele Super Duty Complete Upperupper

Geissele's Super Duty uppers feature their proven reliability rail, chrome-lined barrels, and impeccable fit/finish. Available in 11.5", 12.5", 14.5", and 16" configurations.

Buy
Geissele SSA Triggertrigger

Two-stage match trigger

$279.49Buy
VLTOR A5 Complete Buffer Kitgas-component

The A5 system uses a rifle-length buffer tube with intermediate buffer weights for smoother cycling and improved reliability.

$85.46Buy
B5 Systems SOPMOD Stockstock

Enhanced carbine stock with angled cheek weld and battery storage

$95.00Buy
Aero Precision M4E1 Stripped Lower Receiverlower-receiver

Most popular upgrade lower receiver. Forged 7075-T6 with integrated trigger guard, threaded bolt catch pin, and upper tension screw.

Buy

Best AR-15 Lower Parts Kits

Already have a complete upper? These standalone lower parts kits are ranked by spring quality, detent reliability, and included trigger. The LPK is where cheap kits cause the most problems: weak detent springs, rough trigger pulls, and missing parts.

Budget LPK - Reliable basics

CMMG Lower Parts Kit

  • ✓Mil-spec springs and detents that actually fit
  • ✓Includes basic fire control group
  • ✓Best budget option: proven over thousands of builds
$49.99
View at OpticsPlanet
Mid-range LPK - Bring your own trigger

Aero Precision LPK (No Fire Control Group)

  • ✓Quality small parts without a trigger
  • ✓Pair with LaRue MBT-2S or ALG ACT
  • ✓M4E1 threaded pins available separately
$67.99
View at OpticsPlanet
Duty LPK - Enhanced trigger included

Sons of Liberty Gun Works Liberty Fighting LPK

  • ✓Liberty Fighting Trigger included (6lb pull)
  • ✓No grip included (choose your own)
  • ✓Built for hard use with enhanced detent springs
View at OpticsPlanet
Premium LPK - Complete from Daniel Defense

Daniel Defense AR-15 Lower Parts Kit

  • ✓Complete kit with A2 grip and trigger guard
  • ✓Daniel Defense QC on every component
  • ✓$118 - premium but everything included
$118.00
View at OpticsPlanet

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What to Look for in an AR-15 Build Kit

Barrel Quality

Chrome-lined, cold hammer forged (CHF) barrels last 20,000+ rounds. Nitride-treated barrels are cheaper and accurate but wear faster (10,000-15,000 rounds). PSA uses FN CHF barrels (same supplier as military contracts). Avoid kits that do not specify barrel treatment.

Lower Parts Kit Springs

Mil-spec rated springs are non-negotiable. Weak detent springs cause the safety selector and takedown pins to walk out under recoil. CMMG, Aero, and BCM all use properly spec'd springs. If a kit does not name the LPK manufacturer, assume the springs are garbage.

Gas System

Mid-length gas on 16" barrels is the modern standard (softer recoil, less fouling than carbine-length). Carbine gas on 10.5-14.5" barrels. Avoid 16" barrels with carbine gas, they are over-gassed and beat up the rifle. BCM's conservative gas port sizing is the gold standard.

Bolt Carrier Group

Carpenter 158 or 9310 steel bolt, MPI (magnetic particle inspected) and HPT (high pressure tested). These are the minimum specs. Phosphate coating is standard, nitride is fine, nickel boron is easier to clean. Geissele's nanoweapon coating is the premium tier.

Common AR-15 Build Kit Problems

Weak detent springs: The #1 issue with cheap LPKs. The safety selector will not engage firmly, or takedown pins walk out under recoil. Fix: replace springs from a quality LPK (CMMG kit is $30).

Gritty mil-spec trigger: Every kit under $900 ships with an 8-9lb gritty trigger. This is normal, not a defect, but it makes shooting less enjoyable. Fix: upgrade to a quality trigger (LaRue MBT-2S at $115 is the standard recommendation).

Missing small parts: Budget kits sometimes ship without a trigger guard roll pin, buffer retainer, or detent. Inventory every part before you start building. Cross-reference against the complete parts list in our build guide.

Over-gassed uppers: Cheap complete uppers often have oversized gas ports. Symptoms: excessive recoil, blown primers, accelerated wear. BCM specifically addresses this with conservative port sizing. For other brands, an adjustable gas block is the fix.

No BCG or charging handle: Some "complete" uppers do not include a BCG or charging handle, especially from Aero. Always check the listing description. Budget $80-150 extra if the upper is barreled only.

Best Trigger Upgrades for AR-15 Build Kits

The single biggest improvement to any AR-15 build. If your kit came with a mil-spec trigger, these are the upgrades worth the money. See our full trigger guide for detailed comparisons.

Budget - $65

ALG Defense ACT Trigger

  • ✓Designed by Bill Geissele
  • ✓Smoothed mil-spec single stage (6lb)
  • ✓Best trigger under $80
$82.95
View at OpticsPlanet
Best Value - $115

LaRue MBT-2S Trigger

  • ✓Two-stage, 4.5lb total pull
  • ✓Competes with triggers 2-3x the price
  • ✓Most recommended upgrade in the AR community
$114.99
View at OpticsPlanet
Premium - $240

Geissele SSA Trigger

  • ✓Industry standard two-stage trigger
  • ✓4.5lb total pull with clean break
  • ✓Used by military and LE
$279.49
View at OpticsPlanet

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AR-15 Build Kit vs Individual Parts

Buy a Kit When:

  • - First build and you want guaranteed compatibility
  • - You want everything from one manufacturer
  • - PSA is running a sale (kits drop below $400)
  • - You do not have a specific trigger or stock preference
  • - You want warranty coverage from a single source

Buy Individual Parts When:

  • - You want a better trigger than the kit includes
  • - You want to mix tiers (BCM upper + budget lower)
  • - You already have parts from a previous build
  • - You want a specific barrel length or profile
  • - You are building a specialized purpose rifle

Best of Both: The Mix-and-Match Build

The most common approach among experienced builders: buy a BCM or Aero complete upper, pair with a CMMG LPK ($30), LaRue MBT-2S trigger ($115), Magpul MOE SL stock ($55), and a mil-spec buffer tube kit ($35). Total lower build: ~$235. Better trigger than any kit includes, and the upper is the part that actually matters for accuracy and reliability.

Frequently Asked Questions

▶Who makes the best AR-15 build kits?
PSA makes the best budget AR-15 build kit ($450-550) with FN CHF barrels. Aero Precision is the best mid-range ($650-850) with M4E1 receivers and Atlas handguards. BCM is the duty-grade standard ($950-1,200) with conservative gas ports and excellent QC. Geissele is premium ($1,400-1,800) with REBCG and SSA triggers included. For most first-time builders, the Aero Precision tier offers the best balance of quality and value.
▶Is it cheaper to buy an AR-15 build kit or individual parts?
Build kits save 10-20% over buying individual parts at full price, but the real savings depend on timing. PSA runs frequent sales where a complete kit drops below $400. Buying individual parts lets you cherry-pick: a CMMG LPK ($30), LaRue MBT-2S trigger ($115), and PSA complete upper ($350) totals ~$495 and gives you a better trigger than any kit includes. The kit advantage is convenience and guaranteed compatibility. The individual parts advantage is a better trigger and exactly what you want.
▶What is included in an AR-15 build kit?
A complete AR-15 build kit typically includes: 1) Complete upper assembly (barrel, handguard, gas system, BCG, charging handle), 2) Lower parts kit (trigger, safety, mag catch, bolt catch, springs, detents, pins), 3) Buffer tube kit (buffer tube, buffer, buffer spring, end plate, castle nut), 4) Stock and pistol grip. You still need a stripped lower receiver purchased separately through an FFL. Some kits sell the upper and lower parts separately, so check exactly what is included before buying.
▶What should I look for in an AR-15 lower parts kit?
Quality springs and detents are the most important parts of an LPK. Cheap kits use weak detent springs that cause the safety selector or takedown pins to walk out. Check for: mil-spec rated springs (not generic), properly sized detents (undersized detents cause the safety to not engage), and a trigger guard that fits without forcing. CMMG, Aero Precision, and BCM all make reliable LPKs. Skip no-name Amazon kits, they cause 90% of first-build problems.
▶Do I need an FFL to buy an AR-15 build kit?
No FFL is needed for the kit itself. AR-15 build kits ship directly to your door because they do not include a serialized lower receiver. The stripped lower receiver is the only part legally classified as a firearm and must be purchased separately through an FFL dealer with a background check. Everything else (upper, barrel, LPK, stock, buffer kit) ships to your home with no paperwork.
▶What is the best trigger for an AR-15 build kit?
The LaRue MBT-2S ($115) is the best trigger upgrade for any AR-15 build kit. It is a two-stage trigger with a 4.5lb total pull that competes with triggers costing 2-3x more. For budget builds, the ALG ACT ($65) is the best trigger under $80 (designed by Bill Geissele). For premium builds, the Geissele SSA ($240) is the industry standard. Most kit triggers are basic mil-spec (8-9lb gritty pull) and should be upgraded.

Complete Your Build

Essential accessories to round out your setup

Illumination • $119

Streamlight ProTac HL-X

  • ✓1,000 lumens
  • ✓50,000 candela
$97.99
View at Amazon
Slings & Retention • $75

Magpul MS4 Dual QD Sling

  • ✓Dual QD swivels
  • ✓Convertible design
$66.45
View at OpticsPlanet
Iron Sights • $99

Magpul MBUS 3

  • ✓Impact-resistant polymer
  • ✓Spring-loaded flip-up
$35.95
View at OpticsPlanet
Slings & Retention • $22

Magpul QD Sling Swivel

  • ✓QD swivel
  • ✓Manganese phosphate
$13.95
View at OpticsPlanet
Slings & Retention • $69

Blue Force Gear Vickers Sling

  • ✓Padded
  • ✓Quick-adjust
$62.95
View at Amazon
Slings & Retention • $25

BCM M-LOK QD Sling Mount

  • ✓M-LOK
  • ✓QD socket
$17.85
View at OpticsPlanet

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AB
ABAuthor

Avid shooter with 9+ years of experience including competition shooting. Built 10+ AR-pattern rifles and several handgun platforms for home defense, competition, and suppressed night shooting.

9+ years shooting experienceCompetition shooterBuilt 10+ AR-pattern rifles

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