Tools for Leverage (Wrenches)
The AR needs lots of things to be tightened and torqued. Wrenches are absolutely essential.
R: Required
r: Recommended
O: Optional
Armorer's Wrench (R*)
An armorer’s wrench is a multi-tool for building ARs. It isn’t the best tool for any particular job, but it can get you through many builds with one wrench.
We recommend the Midwest Industries Pro Armorer’s Wrench for a few reasons. It covers a lot of tools, including free float handguard barrel nut wrench, A2 receiver extension wrench, castle nut wrench, 3/4″ muzzle device wrench, hammer, and bottle opener. It also has two 1/2″ square drive sockets on opposite ends of the tool, which allows you to keep the torque wrench drive as close to the wrench axis as possible. It is constructed of 4140 steel, so it is durable.
If you elect to use an armorer’s wrench in place of individual wrench heads, you may be able to forego some of the other wrenches below.
Barrel Nut Wrench (R*)
A barrel nut wrench is necessary for tightening the barrel nut (obviously). At the very least, this secures the barrel to the receiver. For some uppers or handguards, it also serves as a handguard mounting point.
If you need to buy a barrel nut wrench, we recommend the Real Avid wrenches.
Note that if you are building on the Aero Precision Enhanced Uppers (non-threaded M4E1 or M5), the upper comes with the required barrel nut wrench.
Castle Nut Wrench (R*)
The castle nut wrench allows you to tighten the castle nut, which secures the receiver extension and end plate to the lower receiver for pistols and carbines.
If you need to buy a castle nut wrench, we recommend the Real Avid Castle Nut Wrench. It has both a recessed side (which helps prevent slipping and damage to the receiver extension and castle nut) and an extended side (which allows you to reach past any obstructions).
Note that you only need a castle nut wrench if you are building a carbine or pistol. If you are building a rifle (with a rifle receiver extension), you will need a 5/8″ wrench.
A2 Receiver Extension Wrench (R*)
If you are building a rifle with a rifle receiver extension, you will need a 5/8″ wrench. This will allow you to properly torque the receiver extension.
Note that standard 1/2×28 pattern muzzle devices often use 5/8″ wrench flats as well, so if you are building a rifle, this may serve both purposes.
We recommend the Real Avid 5/8″ Wrench.
Muzzle Device Wrench (R*)
Your muzzle device will need to be properly torqued. The right muzzle device wrench will allow you to do so confidently, without damaging the device.
We recommend the Real Avid muzzle device wrenches. They offer multiple sizes, as well as an adjustable wrench head.
Note that some muzzle devices come with the required muzzle device wrench (e.g. Precision Armament HYPERTAP, VG6 Epsilon).
The table below identifies the required wrench for some common muzzle devices:
| Device | Type/Flat Span | Recommended Tool |
| A2 Flash Hider 5.56mm | 0.750″ | 3/4″ Wrench |
| A2 Flash Hider 7.62mm | 0.750″ | 3/4″ Wrench |
| Noveske KX3 5.56mm | 0.750″ | 3/4″ Wrench |
| Precision Armament EFAB 5.56mm | 0.750″ | 3/4″ Wrench |
| Precision Armament EFAB 7.62mm | 0.750″ | 3/4″ Wrench |
| Precision Armament Hypertap 5.56mm | Spanner or 0.828″ | Included (no torque) or Adjustable Crowfoot Wrench |
| Precision Armament Hypertap 6.5mm | Spanner | Included (no torque) or Adjustable Crowfoot Wrench |
| Precision Armament Hypertap 7.62mm | Spanner | Included (no torque) or Adjustable Crowfoot Wrench |
| Precision Armament Hypertap 9mm | Spanner | Included (no torque) or Adjustable Crowfoot Wrench |
| Precision Armament M4-72 5.56mm | 0.750″ | 3/4″ Wrench |
| Precision Armament M4-72 7.62mm | 0.750″ | 3/4″ Wrench |
| Precision Armament M11 5.56mm | 0.985″ | Adjustable Crowfoot Wrench |
| Precision Armament M11 6.5mm | 0.985″ | Adjustable Crowfoot Wrench |
| Precision Armament M11 7.62mm | 0.985″ | Adjustable Crowfoot Wrench |
| Surefire 3-Prong SOCOM Flash Hider | 3-Prong or 0.750″ | 3-Prong Wrench or 3/4″ Wrench |
| VG6 Epsilon/Epsilon SL 5.56mm | 3-Prong | Included |
| VG6 Epsilon 7.62mm | 3-Prong | Included |
| VG6 Epsilon 9mm | 3-Prong | Included |
| VG6 Gamma/Gamma SL 5.56mm | 0.750″ | 3/4″ Wrench |
| VG6 Gamma 7.62mm | 0.750″ | 3/4″ Wrench |
| VG6 Gamma 9mm | 0.750″ | 3/4″ Wrench |
Torque Wrench (R)
The wrench heads allow you to engage the parts that need to be tightened. But all parts need to be tightened to the appropriate torque. A torque wrench is absolutely essential.
We love the Quinn Digital Torque Wrench available at Harbor Freight. It gives you 12.5-250 ft. lbs. of measurement, visual and audible warning, and works in both directions.
If you want something more affordable, the Tekton analogue/click wrenches available on Amazon.com are very good.
Breaker Bar (r)
A breaker bar is strongly recommended for all builds. Before you torque most things, you should “exercise” the threads by tightening and loosening the part a couple of times. This results in a better mating of threads and distributes lubricant/thread locker.
A breaker bar should also be used for removing torqued/staked parts. The amount of reverse torque needed to do so can damage the torque drive of most wrenches.
You don’t need anything fancy here. The Neiko 18″ breaker bar is what we use.
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