AR15 can be assembled in many different ways, and this guide can't go over everything, but we will cover an good AR15 upper build parts list from budget to expensive. So be sure to bookmark this page for future references.
In the gun world, there are many things that you absolutely don't need. Some are extremely fancy, some are not practical, and some are things you may never use. This guide focuses on a practical AR15 upper build that won't destroy your bank account.
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AR15 Upper Receiver Build Options
Upper receiver now days can get extremely fancy, so for budget options, I recommend the standard BCM if you can find one available. Aero Precision is also a good option, but the tolerance can be off sometimes compared to something like a Daniel Defense. Anyway, here are some good budget options:
For higher end options:
AR15 Bolt Carrier Group Options
AR15 bolt carrier group is one of the major parts that makes the rifle run. Most AR15 BCGs on the market today are full auto rated, but this doesn't mean the rifle is full auto without the full auto trigger system
There are many options available with various coating (Smooth cycling definitely matters) and for a budget build, these are recommended:
On the higher end. These are recommended:
AR15 Barrel Options
For a legal barrel length AR15 chambered in 5.56, a 16" long barrel is required (Not accounting for the length of the muzzle device). There are many AR15 barrels available, and these are our recommendations between budget to mid price range.
For 16" barrels. Ballistic Advantage 1:8 Hanson profile barrel is the best without spending a ton of money. The barrel however requires dimple to secure the gas block. The 1:8 twist rate is best for 50, 55 and 62 gr bullets, and 62 grain bullet gives you some stopping power to knock down steel spinner targets for competition shooting without wasting ammo.
1:7 twist rate is good for 77 grain bullet if that's what you want to shoot.
For the higher end stuff, here are the best in the price range of $250 - $300
- Daniel Defense cold hammer forged barrel
- FN cold hammer forged barrel
The options are endless, and this guide can't include all of them, please see the AR15 barrel guide to see more
For 300 Blackout barrels please go here
Gas System
For a direct impingement AR15 build, there are so many options available for the 5.56 platform, and they all do the same thing. If the handguard goes over the gas block, be sure to use a low profile gas block and either pin it to the barrel, or tighten it with a set screw where you dimpled the barrel.
0.750" diameter size gas block is the most common for most barrel profiles. Just buy the gas tube that fit the gas length of your barrel. Aero precision offers the most affordable gas block and gas tube:
To learn more about AR15 gas tube length here
AR15 Charging Handle
The Radian raptor charging handle is the best. It offers the best ambi control feature among others, and its the most popular.
If you want something else, these are your options:
They are all round the same price range and some versions are cheaper.
AR15 Handguard Options
There are plenty of AR15 handguards available. MLOK is the most popular today because it saves a lot of weight compared to M1913. Keymod is still popular.
As far as building the most rigid handguard system. The Geissele and BCM offers the best products.
In the context of building a 16" barrel AR15, a 9 inch or 13 inch handguards are my personal favorite because they provide just enough rail space. Anything longer than that maybe wasteful if you don't plan on mounting accessories.
AR15 Builder Tools
AR15 upper parts are fairly simple to put together. While they are marketed as "LEGO" alike, but there are components that need careful tolerance check and alignment for the perfect build.
Here are must have tool to get:
- Midwest Industries Reaction Rod - Ensure barrel extension and index pin alignment before applying torque on barrel nut
- SAAMI Go/No Go gauge - Ensure the proper and safe chambering of rounds in firearms
- Vice clamp - A work bench is needed to mount the vice clamp to torque the barrel nut and muzzle device