How Do I Build a Quality AR-15 for Under $800?
A reliable, accurate AR-15 can be built for $600 to $800 by using an Aero Precision M4E1 lower ($80 to $100), Aero complete upper ($300 to $350), a quality LPK with upgraded trigger like the LaRue MBT-2S ($130 total), Magpul furniture ($60 to $80), and a Sig Romeo 5 red dot ($120). This build will outperform most factory rifles costing $1,000 or more.
Why It Matters
Many first-time buyers believe they need to spend $1,500 or more for a quality AR-15, or they go too cheap and buy a $350 rifle that has problems. The $600 to $800 range is the sweet spot where you get genuinely reliable, accurate components without paying for brand premium or features you do not need. Building it yourself also teaches you how the rifle works, which is invaluable for maintenance and troubleshooting.
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Budget AR-15 build parts list:
Lower receiver — $80 to $100:
- Aero Precision M4E1 stripped lower: best budget lower, threaded bolt catch pin, integrated trigger guard, excellent fit
- Palmetto State Armory (PSA) stripped lower: $50 to $60, widely available, mil-spec, reliable
- Ruger Harrier lower: ~$550 for complete rifle, built at the old Anderson facility after Ruger acquired Anderson in July 2025 — the new floor for acceptable budget ARs
- Note: Anderson Manufacturing brand is discontinued — Ruger shut it down after acquisition and replaced it with the Harrier line
Lower parts kit — $30 to $50 (without trigger):
- CMMG mil-spec LPK without grip or trigger: $25 to $35
- Aero Precision LPK without trigger: $30 to $40
- Add LaRue MBT-2S trigger: $100 (best value trigger available)
Pistol grip — $18 to $25:
- Magpul MOE+ ($22): rubberized, comfortable
- Magpul MOE ($18): standard polymer, lighter
- BCM Gunfighter ($20): excellent grip angle
Buffer kit — $30 to $40:
- Aero Precision mil-spec buffer kit: tube, castle nut, end plate, buffer, spring
- Carbine buffer (3.0 oz) for standard 16-inch mid-length builds
Stock — $30 to $50:
- Magpul MOE Carbine ($30): simple, lightweight, proven
- Magpul SL ($50): better cheek weld, QD sling mount
- B5 Bravo ($50): excellent cheek weld, slim profile
Complete upper — $300 to $400:
- Aero Precision M4E1 16-inch complete upper ($350): mid-length gas, free-float handguard, includes BCG and charging handle
- PSA 16-inch mid-length complete upper ($300): budget option, reliable
- BCM standard 16-inch upper ($550): premium quality, worth the stretch if budget allows
- Buying a complete upper saves time and ensures headspacing is checked
Optic — $120 to $150:
- Sig Romeo 5 ($120): shake-awake, 2 MOA dot, excellent value
- Holosun HS403B ($140): 50,000-hour battery life
- These compete with optics costing 3x more
Total build cost:
- Budget tier: $550 to $650 (PSA lower, PSA upper, Romeo 5)
- Sweet spot: $650 to $800 (Aero lower, Aero upper, LaRue trigger, Romeo 5)
- Stretch: $800 to $1,000 (Aero lower, BCM upper, LaRue trigger, Holosun 510C)
Where to save money:
- Lower receiver: PSA is functionally identical to expensive receivers at half the price
- Furniture: Magpul MOE series is inexpensive and excellent
- Charging handle: mil-spec is fine to start (upgrade later)
Where NOT to save money:
- Barrel: this determines accuracy — Aero, Ballistic Advantage, or Faxon minimum
- Bolt carrier group: Toolcraft is the best value ($70 to $80), used by many brands
- Trigger: the LaRue MBT-2S at $100 is the best upgrade-per-dollar in the build
Build Impact
Buy parts over 2 to 3 months if paying cash — barrel and upper first, lower and parts kit next, optic and furniture last. Watch for sales on Black Friday, Memorial Day, and 4th of July — AR parts regularly go 15 to 25 percent off. A complete upper from Aero or PSA is the fastest path to a functional rifle — combine it with a stripped lower and LPK and you can have a complete rifle in an afternoon. Budget $150 to $200 for initial ammunition (500 rounds) and a basic rifle course.