How To Build An AR15 Cheap [Up to $1000]

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If you can't find an AR15 you like in your local store - you can just build one for under $1000 and yes it's doable!

This guide shows how to build an AR15 cheap and reliable.

Sometimes spending more doesn't really make much of a difference if the important support accessories are not on the rifle.

Let's find your parts now.

Build A Top Notch Budget AR!

holosun-510c-on-smith-wesson-mp15-sport-2

Note: This guide only covers standard 16" 5.56mm barrel builds

Building a good rifle it's just like building cars, bikes, desktop computers, and many other things in life. Knowing exactly what parts to get to increase performance and eliminate wasteful spending is the key to build a bad ass AR15.

Ball Park Cost - Around $700 - 900 is considered "cheap" or "low cost" in the AR15 world for a fully functional rifle (Not including many useful accessories)

Like A Lego Set - Many ways to make the rifle more unique than the others

Build Your Dream Rifle - Clone your dream rifle from movies, military history, and video games.

What To Expect From A High-End Rifle - Generally costs around $1700 and $2000. Some have the same parts as a basic AR but are packaged with other bells and whistles to up the price tag. An experienced AR person can quickly spot the difference.

Minimum Tools Required

  • Punch pins & small nylon hammer
  • AR wrench & Torque wrench
  • Workbench vise clamp
  • Chamber gauge
  • AR receiver block insert

If you don't want to invest in tools to just build one rifle, buying a complete rifle or receiver set will be a better cost saving option.

Check out best AR15 complete upper receiver 

Parts Cost Priority - Low Cost AR15 Build

  1. Barrel - Don't cheap out on the barrel even for a budget build
  2. Trigger - Makes a huge difference
  3. BCG - This is the engine of the rifle
  4. Buffer Spring - For better BCG return force & service life
  5. Stock - Must have
  6. Pistol Grip - Must have
  7. Handguard - Mount accessories
  8. Muzzle Device - Reduces muzzle shift & sway
  9. Other accessories - Optional

Best Parts To Buy For An Upper Receiver

bcm mk2 bfh mid length upper

A basic upper receiver consists of the following items:

  • Barrel 
  • Muzzle device
  • Main receiver
  • Gas block
  • Gas tube
  • BCG (Bolt Carrier Group)
  • Charging handle
  • Front & rear sights (Optional for some builds)
  • Dust cover (Optional)
  • Forward assist (Optional for some)
  • Optic

Main Receiver

ar15 upper receiver

To make it low cost and reliable, the standard A2 works just fine.

Whether you spend $350 for a receiver or a $90 receiver, the $90 receiver is a better choice so you can allocate the money to buy something more expensive such as a good trigger and handguard.

BCM

Anderson MFG

Aero Precision

Palmetto State Armory

Barrel

ar15 barrel 16 inches

The barrel is the most important part of the rifle, and buying a 1:9 twist rate barrel with the following specs, and you're good to go:

  • Cold hammer forged - Exceptional strength, grain structure, accuracy & finish
  • 1:9 twist rate - Works well for 45 - 70 gr 5.56mm or 223 bullets
  • Mid length gas system - For a standard 16" build, the best is mid-length gas system
  • Medium (Government Profile) - Heavier than pencil barrel with a balanced weight and durability

Check out these awesome barrels:

Spike Tactical 

Faxon 

Daniel Defense

Ballistic Advantage

Gas Block & Tube

gas tube and gas block

Must match the gas tube length to the barrel the gas system is designed for.

In this guide, we recommend getting a mid length gas system, so a mid length gas tube is required.

If you're going with a free float handguard configuration, a low profile gas block is required.

Bolt Carrier Group

aero precision bcg nickel boron

Most AR15 BCG on the market today are full auto rated, coated, gas key staked, HPT & MPI tested (Doesn't mean it will go full auto)

The BCG experiences the most stress on the rifle during cycling, so getting a high quality bolt without getting too fancy will get the job done.

  • Nitride coated - Easier to clean
  • Nickel Boron - Shiny, butter smooth & easier to clean
  • Titanium Nitride - A bit exotic product for a high end AR build

There are many choices, for a budget build, please check out these:

PSA BCG - The Lowest Price

Bravo Company Manufacturing M16 BCG - Gunfighter's Favorite Brand

Brownells Nitride M16 BCG - Best Value

Faxon Lighweight BCG - Lightweight BCG Action

Charging Handle

aero precision ar15 charging handle

For a budget build, a standard mil-spec charging handle will do just fine. If there is money left over, we highly recommend the ambi Radian Raptor charging handle

Forward Assist

For a reliable AR15 build, get the receiver with the forward assist to help you seat the bolt just in case.

Handguard

BCM MCMR handguard

Free Float Handguard - More Mounting Spots, Better Barrel Harmonics & Features Anti Rotational Receiver Tab

Removable front sight required

magpul m lok handguard

Two Piece - Much Cheaper Option, Requires Old School Delta Ring 

The handguard in many ways defines the rifle, and it's a large visible part of the rifle that enables accessories mounting and the way it looks and feels.

Why Does A Good Handguard Matter?

  • A place to grab the rifle 
  • Mount lights and lasers
  • Sling and grip attachments
  • Mount bipod

If you don't plan on further upgrading the rifle or adding accessories, this will be optional and it will save you a lot.

For A budget build, these are the best options:

BCM MCMR Free Float Rail - 9", 10", 13" & 15"

Midwest Industries G3M

Magpul MLOK Polymer Handguard

By now you should probably have some ideas on what you can financially and  responsibly afford to get all the parts you need. 

Another way is to just buy a cheap rifle like the Smith Wesson M&P 15, and add a light, a sight and a sling later.

Check out these good AR15 you can buy for $1000 here.

Best Parts To Buy For An Lower Receiver

ar15 lower receiver
ar15 lower parts kit
aero precision AR15 M4e1 lower receiver

The lower receiver build concept is similar to the upper receiver.

A basic lower receiver consists of the following items:

  • Trigger (It's worth spending more on the trigger that you will not regret)
  • Trigger guard
  • Pistol grip
  • Bolt catch
  • Battery Assist Device (Optional)
  • Magazine release
  • Safety selector
  • Retainer pins
  • Stock
  • Buffer tube
  • Buffer spring and buffer (Try Geissele Braided Wire Spring to)

You can get most of them in a lower parts kit including a mil-spec trigger

Trigger

Timney-Single-Stage-Trigger

A drop-in trigger is highly recommended to make a low-cost AR shoot like a high-end rifle. A good trigger is by far the number 1 performance increase shooters immediately notice when comparing with other similar ARs.

A great aftermarket trigger will provide a better trigger pull experience for tighter group shots at longer distances, and a better trigger reset for fast follow-up shots.

Timney Single Stage Trigger

Geissele Combat Trigger

CMC Drop In Trigger

ALG ACT Trigger

Grip

bcm ar15 pistol grip MOD 2

A good grip makes a huge difference in how the shooter feels around his/her wrist in terms of biomechanics when operating the AR15 platform, and it's inexpensive.

Get a PDW steep angle grip, the BCM MOD 2 grip is by far the best.

  • Allows shooter's wrist to stay in a neutral position without adding strain to the firing hand
  • Great for PDW build
  • Adds just a little bit more speed and less finger strain while shooting fast
  • Slightly faster weapon draw from the low ready position
  • Just looks and feels better in the hands

If you have a large hand, there are customizable AR15 grips for large hands that come with multiple different size grip panels to fit your need.

Buffer Tube

buffer tube

There are commercial and mil-spec buffer tubes. They do the same thing and they fit on any lower receivers you may have

  • Mil-spec tube goes with a mil-spec stock.
  • Commercial tube goes with a commercial stock AND Mil spec

Learn more about their spec differences here

We recommend just buying the tube instead of a complete set so you can allocate some money for something else.

Buffer Spring

braided-buffer-spring

We highly recommend the Geissele Super 42 Braided Wire Spring for its improved spring cycling harmonics and service life. Most importantly it eliminates the annoying AR15 twang sound in the buffer tube when firing.

It's the same spring we recommend on other high-end rifles including SBR builds, and definitely add this to the cart.

Rifle Stock

magpul CTR stock black

A good rifle stock makes a big difference in how sturdy the rifle feels when shouldered, and it makes the rifle feel very rock solid without any wobble.

There are tons of options out there, and to make it simple get the following:

Magpul CTR stock - Very good start for less than $70

BCM

These also have built-in sling attachment points.

Other Accessories

After the base rifle is built, it's up to you to get all the accessories including optics.

The most common accessories for a home defense AR15 are:

A good optic today costs around $200 and can go as high as $890 for a red dot sight.

Many people find the price of an optic to be ridiculous, but a good optic with a good mount stays on the rifle tight and holds the zero.

Click here for more low power variable scopes

Wrap Up

Building a low-cost AR15 is fun and educational! 

Through the process, it also teaches you the AR15 system and what parts actually move the needle in terms of performance.

The parts a budget AR should spend more on are:

  • Barrel
  • Muzzle brake
  • Trigger
  • BCG

Sverre B

A prior military-civilian employee in government contracting 13 years of experience in 3D Printing and manufacturing. 6 years of experience with firearm tooling and hunting