When people talk about “building” an AR-15 they are effectively talking about “assembling” an AR from parts. The surging popularity in the AR platform is in no small part due to the ease with which the hobbyist can assemble one with minimal special tooling. However, having the right tool for the job is always a good idea and judicious investment in a few tools will simplify the build process and reduce the risk of damage.

I thought I would share my perspective on the tools I have purchased specifically for AR assembly, as shown in the picture above. Most people already have a base set of tools such has screwdrivers, wrenches, and hammer so I won’t spend much time discussing common tools. This isn’t presented as advice or as the “optimum” solution; I’m simply sharing the results of the decisions I’ve made regarding tools to date. So, here is my list of what I find to be my essential tools for AR building:

1. Wilton 4” Mechanics Vise (Model 744); Source: E-Bay; Street Price $110-$150
2. Squirrel Daddy AR-Style Upper and Lower vise block R3.0 and top rail protector (SD20-172); Source: SquirrelDaddy.com; MSRP $26.95
3. Grace USA Roll Pin Punch Set 7-Piece Steel; Source: MidwayUSA; MSRP $32.99
4. Schuster AR-15 Roll Pin Starter Punch Set 2-Piece Steel; Source: MidwayUSA; MSRP $19.99
5. Light hammer with brass and plastic inserts; Source: Harbor Freight; ~$6
6. Squirrel Daddy Gunsmiths detent pin and spring installation tool (SD20-180); Source: SquirrelDaddy.com; MSRP $6.49
7. Tapco Enhanced AR-15/M4 Stock Wrench; Source: Primary Arms; MSRP $12
8. SK Hand Tool 76130 1/2-Inch Drive Endam Type Torque Wrench Box, 150-Feet Pound; Source: Amazon.com; Street Price $70
9. Geissele Reaction Rod; Source: Primary Arms; MSRP $100 (sale price $70)
10. Husky 1/2 in. Drive 15 in. Breaker Bar; Source: Home Depot; MSRP $20
11. DPMS Barrel Vise Jaws; Source: Sportsmansguide.com; MSRP $20

First things first, it’s good to be able hold the firearm (or receiver) firmly in place and hands free while working. You’ll want both hands free to work on that task at hand. To that end, a good bench vise was one of my first purchases. I spent more and got a vise that is arguably heavier than really required for building an AR, but I wanted a vise I could also use for other general shop purposes. A good vise pretty much lasts forever and is indestructible but don’t expect that from many of the cheap imports made from low quality castings that are currently on the market. That said, building an AR isn’t terribly demanding on a vise, so one could easily spend much less than I did and be just fine.

One side note is that a good vise will need a sturdy bench on which to be mounted. My workbench is a simple fold out wood workbench from Home Depot that cost about $70 (http://www.homedepot.com/p/Unbranded...2X22/203083493).

A vise by itself won’t be much help with building an AR if you also don’t have a good set of receiver vise blocks. Vise blocks are held by the jaws of the vise and hold either the upper or lower receiver. Some vise blocks on the market can be surprisingly expensive so I was pleased when I found a very affordable set from Squirrel Daddy that included both lower and upper vise blocks, plus a top rail cover if you need to hold the upper receiver horizontally (Picture 3). I’m using either the upper or lower vise block pretty much all the time when I’m working at my bench. The lower vise block is a great way to secure the lower receiver during LPK installation or to hold a complete AR for minor work such as scope installation (Picture 4). I’ve also found that using the upper receiver vise block to hold the complete upper is the easiest way to clean the barrel after a trip to the range.

Picture 2: Squirrel Daddy upper receiver vise block with top rail protector holding an Aero Precision M4E1 Upper receiver


Picture 3: Lower receiver vise block


With the lower receiver held in place on a lower vise block you are ready to install a Lower Parts Kit. As their name implies, roll pin starter punches simplify getting the roll pins started. They have recessed holes to hold the roll pin while you tap it into place. You won’t be able to drive the roll pin all the way in with a starter punch, though, so switch to a roll pin punch to finish the job. A light brass hammer helps minimize the damage if you miss and helps deliver an appropriate level of force. Keep in mind many people successfully install LPKs using just a hammer and a $3 nail punch, but a proper set of roll pin punches will likely speed up the process and reduce the chances of damage to either the LPK or the receiver.

One “nice to have” but non-essential tool is a detent pin installation tool used to simplify installing the pivot pin on the lower receiver. This step in building an AR is the most likely occasion to have a spring going flying across the shop/garage to never be found again, so an extra $7 was worth the potential lost time and frustration for me.

Assembly of an adjustable stock carbine lower receiver will also require a special wrench to tighten the castle nut on the buffer tube. While most AR armorer’s wrenches have this capability, I chose to go with a dedicated stock wrench since I have yet to assemble an AR using a standard barrel nut so have never needed a basic Armorer’s wrench.

Moving on to the upper receiver, the focus of the assembly is on the installation of the barrel which typically requires a torque wrench to ensure proper tightening of the barrel nut. After reading many negative reviews of popular consumer “Click” torque wrenches and learning that their reliability and calibration can be problematic, I opted for a traditional beam style wrench. While hard to find in your local big-box store, beam style wrenches have the advantage of providing a continuous readout of torque, being easy to calibrate, and having fewer parts to break. As a bonus, they are actually also generally less expensive.

When applying torque to the barrel nut, you’ll want to ensure the upper receiver is held firmly in place in the vice. While I already had the above mentioned standard Delrin upper vise block, I picked up a Geissele Reaction Rod during a sale and much prefer it over the standard and clamshell styles. The Reaction Rod engages the locking lugs of the barrel extension instead of the receiver itself. The only downside to the Reaction Rod is the price. There are a few similar and cheaper concepts on the market. Also, Magpul has released the BEV Block since I made these purchases and if I was starting from scratch today would consider that tool in lieu of my existing lower vise block and Reaction Rod. However, one advantage of the Reaction Rod is the ability to rotate the assembly enabling you to hold the upper receiver assembly upside down or on its side. This can be handy during handguard installation.

Picture 4: Geissele Reaction Rod


A breaker bar is also highly recommended for removal of barrel nuts, including during the process of repeatedly tightening/loosening the barrel nut during installation. It’s best to save your torque wrench for the situations that require proper torque. In other words, use the torque wrench to tighten and the breaker bar to loosen. While I already had a good socket wrench in my toolbox that I have could have used for this purpose, I chose to add the $20 breaker bar to my set.

Using barrel vise jaws allows installation of a muzzle device without putting unnecessary torque on the upper receiver or barrel extension. Barrel vise jaws border on being “nice to have” as I’ve certainly managed to install muzzle devices using the “hold-the-rifle-between-your-legs” method, but given their low cost they are a worthy addition. Also, I’ve wasted time and ammo at the range before as I watched my group size open up with great frustration only to ultimately realized that my muzzle device had loosened up and backed off considerably because I didn’t install it with sufficient torque. That lesson probably cost me $20 to $30 in wasted match grade ammo.

Not shown and not a tool but worth mentioning is AeroShell 33MS grease. This is used to lubricate the threads and shoulder of the barrel extension when installing the barrel. The trouble with 33MS is it is sold for use in maintaining aircraft which means it comes in large tubes running about $30 that would provide enough for a few thousand rifles. Luckily, this problem is easily solved thanks to people who resell it on eBay in small quantities for a few bucks. One ounce will cover several builds.

As you can see, I’ve spent around $400 on tools which is why people are quick to point out that building an AR instead of purchasing a factory rifle doesn’t really save money. Clearly, though, one can get by with spending much less but some shortcuts might lead to expensive, time consuming, or embarrassing mistakes. It’s not too hard to find examples of mistakes that could have been prevented with the proper tools.