Tools for Building an AR-15 Lower

Building an AR-15 lower is doable for just about anyone.  I will discuss what tools you really need, the ones that you don't need, where to get them and how much they cost.

WHAT YOU NEED

First you will need roll pin punches.  Regular punches don't work well on roll pins.  You need the following sizes:
#2  5/64"
#3  3/32"
#4  1/8"
You can buy these from Brownells for $3.99, $4.99 & $4.99 ($13.97 total) or you can buy a set of Lyman #1, #2, #3, #4 punches from Midway for $17.49 or CheaperThanDirt for $15.66.  You won't need the #1  1/16" punch unless you are building the upper (the gas tube pin).  Or you might need it if you buy a bolt separate from the upper.  In order to check head space, you have to remove the 1/16" pin from the ejector.

If you are putting on a collapsible buttstock, you will need a buttstock / castle nut wrench.  You can buy the Tapco wrench from Brownells for $9.99, Midway for $8.39 or CheaperThanDirt for $7.57.

If your lower parts kit uses a phillips head grip screw, you will need a long phillips head screwdriver.  If your parts kit has a hex head screw, you will need a long 3/16" allen/hex bit or socket.  I used a hex bit from my gun screwdriver set (Midway part# 450879 for $10.99).  The screwdriver handle was not long enough to reach the screw, so I extended it with the bit holder from my cordless drill.

WHAT YOU DON"T NEED

You don't need a special hammer.  You can use any old hammer.  When you are tapping in the trigger and hammer pins, you can put some masking tape on the hammer face.

You don't need Brownells special bolt catch punch for $17.99, you can just put masking tape on the side of the receiver to protect it and use a regular roll pin punch.  This would be a nice tool to have if you assemble lower receivers on a regular basis, but you don't need it to build your first AR.

You don't need a special tool for installing the pivot pin.  You can use a 1/4" x 2" cleavis pin that you can buy at Home Depot or Lowes for about 50 cents.  You can also use an Allen wrench that just fits the pivot pin holes.  I like the cleavis pin better.

You don't need roll pin starter punches.  You can just tape the pin to a regular roll pin punch to get it started.

NOT NEEDED, BUT NICE TO HAVE

You don't need a lower receiver action block, but it is nice to have.  Makes everything easier, especially putting on the buttstock.  It is handy for cleaning or working on your rifle later.  You need to have a bench vise to use it.  You can get the Promag model from Midway for $10.49 or CheaperThanDirt for $8.22, or you can make your own, as detailed in my previous post.  Or you could use an old magazine if you have one that you don't mind putting sacrificing to the vise.

You don't need a special tool for installing the pivot pin.  You can use a 1/4" x 2" cleavis pin that you can buy at Home Depot or Lowes for about 50 cents.  You can also use an Allen wrench that just fits the pivot pin holes.  I like the cleavis pin better.  You can put the spring and detent through one of the holes in the pin, push it in with a punch, and then use the punch to rotate it to capture the spring and detent.  Then use the pivot pin to push the clevis pin out of the way.  It works like a charm, and 50 cents is cheap insurance for not shooting the pivot pin spring across the room and not being able to find it.

Other nice to haves are a gunsmith screwdriver set.  You can get these in the $10 and under range.  Also a vise, if you are going to use an action block.

If any of your parts have a rough texture the seems to gather dust and dirt like a magnet, some 0000 steel wool will smooth it out without harming the finish.  A microfiber cloth, like people use to wash their cars, works well for wiping down you weapon.

I'm not going to walk you though the assembly of the lower receiver.  There are some excellent videos on the internet for that.  I highly recommend the Brownells videos.  Go to www.brownells.com, then click on the "Learn" tab, then click on "Build an AR-15".  Word of warning:  Brownells will suggest that you need some of their specialized tools, that you don't really need.  See above tool recommendations.  The CheaperThanDirt videos are also good.  They show you how to do it without all the specialized tools.  http://articles.cheaperthandirt.com/category/ar15/  I would watch all of these videos before getting started.