Completing an AR15 Lower





By: Jarrod Sousa




So you want to build your 1st AR15?  Great!  Putting an AR15 together is the ultimate lego set.  There is no feeling in life like the sense of pride and accomplishment that you just built a rifle with your own 2 bare hands.

But what tools will you need?  Where do I find them?  These were the same questions I had when I ventured out to build my 1st AR lower.  So to save you some time (and OK maybe to help me remember for the next time as well) I put together this list of all the things you will need before you start:

  1. Stripped lower receiver (obviously) – this is the only piece that is considered a firearm according to law.   Everything else is just parts.

  2. A lower parts kit – There are a lot of debates out there on the interwebs about which LPK is best/not good/etc.  Really what the difference between them is the trigger from what I have found.  They will all have a pull weight of about 5.5 to 6 lbs. which is USGI spec.  The difference is how smooth the trigger pulls and resets.  Unless you are a competition shooter though, I would probably just use the standard trigger group and upgrade the optics (just my opinion).

  3. A stock kit – This includes the stock itself, as well as the buffer tube, buffer spring, buffer, end plate, and castle nut.  As with everything else on the AR you can decide to spend some extra cash and upgrade the various parts.  If you are building a larger caliber AR then you may need a heavier buffer to get it to run smoothly, but mostly the stock is just about looks and comfort.

  4. Blue Loctite – #242

  5. Blue painters tape – you will need a lot

  6. Roll Pins Punches – DO NOT GO CHEAP!!!!!!!  You are working with precision machined pins and holes.  China made tools are cheap, but they are not made to quality standards.  You do not want to get halfway through your build to realize that $5 you saved on roll pin punches will prevent you from finishing because it’s .01 inches out of spec.  I have used these punches on all my builds and I will swear by them.  There are others out there but I know these will work and are a fair price.

  7. Roll Pin Starters – These you can go cheap on.  They are extremely helpful in getting the roll pin started into the hole.  I have used these with great results.

  8. Armorers Wrench – You will need this for the castle nut which holds the buffer tube in place.  You can get just a castle nut wrench but for only a few more dollars I would just buy the whole thing.  Sometimes you can find them on , but I like this one from Cobratac.com

  9. Vise Block – I have a Tipton Gun Vise and it works great.  If you don’t that’s OK, any old bench vise with a mylar vise block will do as well.  I found these guys online, for the price you can’t go wrong.  Really all you need is something to hold the lower in place as you work on it so you can use both of your hands.  Small children can sometimes be used as a substitute in a pinch 🙂

  10. Armorers Hammer – I bought this one from Amazon because it has the changeable tips.  It works perfect, remember you are tapping things in place, not beating on them with a 5lb dead blow!

  11. Patience!!! – This one is free, but it will cost you a ton of $$$ if you don’t have it.  Remember that building an AR requires time, and attention to detail.  Don’t try to rush things, and if you get frustrated just take a break and come back to it.  This is your 1st try after all 🙂

There are tons of videos on YouTube to show you how to put all the pieces together step by step.  Just do a search and follow along!

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