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How to Build an AR-15 Lower Receiver [Ultimate Visual Guide]

There’s nothing like assembling your own AR-15 lower receiver for personal satisfaction and customization.

I’ll guide you through everything with minimal tools and tons of tips I’ve learned the hard way!

Complete AR-15 Lowers
Complete AR-15 Lowers

So get ready for A LOT of pictures that will make building your lower a breeze.  Plus a bonus of the upgrades I immediately did to my lower to make it perfect for 3-Gun competitions.

But first…a disclaimer that this is for educational use only.  If you don’t have the right tools or experience, please have this done by a professional or buy a completed rifle (Best AR-15 Buyer’s Guide)

Table of Contents


Parts and Tools


All AR-15 Lower Receiver Parts
All AR-15 Lower Receiver Parts

I went with a California featureless build so there’s the funky looking grip.  But otherwise, everything is pretty standard.

I haven’t found much difference between lower parts kits and buffer tube assembly’s as long as there are decent reviews and not a no-name company:

Lower Kit,
Lower Kit,


  • Punch Set ($15): I prefer brass so you don’t mar up your lower receiver and it’s good for lots of other gun stuff too
  • Long Arm Hex Key Set ($12): You’ll be using hex keys or Allen wrenches in a lot of installations.  Go with the long arm versions for extra reach.
  • Hammer ($10): I like the rubber/plastic ends instead of standard steel since there are very few times when you actually need that much force…also if you use it directly on gun parts, you will not mar the finish
  • C-Clamp ($10): Not super necessary but useful to install the trigger guard, 4-inch should be good
  • AR-15 Combo Tool ($20): Good for installation of the castle nut, but more useful for upper receiver builds
  • Utility Knife ($7): Needed for the pivot pin installation

Alright, let’s get onto the actual build!

Magazine Catch Assembly

Magazine Catch Assembly Parts
Magazine Catch Assembly Parts

You can start your AR-15 lower receiver build many different ways but I like knocking out some of the easier ones first for quick wins.  Find these three parts along with your lower receiver.  The magazine spring is the largest width spring in your kit.

Magazine Release Spring
Magazine Release Spring

Place the magazine release spring into the hole shown above.

Magazine Release Button
Magazine Release Button

Place the magazine release button on top of it with the serrated side up.

Magazine Catch
Magazine Catch

Press in the magazine release button and flip the receiver over to start threading in the magazine catch.  It might be a little tricky the first time you do it since you have to maintain decent pressure on the button to make it flush against the receiver while matching up the threads.  Righty-tighty!

Make sure the catch doesn’t scrape against the raised portions of the receiver.

Screwed in Magazine Release
Screwed in Magazine Release

Once you have it threaded slightly you can release the pressure and rest your fingers for a little.  Then get ready to do it again!  Press down the magazine release even further into the receiver past the flush line and tighten the magazine catch a couple more times.

Gap Between Magazine Catch and Receiver
Gap Between Magazine Catch and Receiver

Check once in a while.  Here you can see that there’s a gap between the mag catch and the receiver when you’re pressing the mag release button flush.  You’ll need to tighten more or else the mag catch could fail to go back into the receiver during a reload.

Correct Distance for Magazine Catch
Correct Distance for Magazine Catch

This is a good distance where the magazine catch will not leave the receiver unless somehow you manage to really smash in the magazine release button.  You can test with some of your mags to make sure it catches and releases.

Congrats!  You’ve installed the first section of your AR-15 lower receiver.

Trigger Guard Assembly

Some lowers have this part as part of the stripped lower…but most likely you’ll have to do it yourself.

Trigger Guard Assembly Parts
Trigger Guard Assembly Parts

Find the trigger guard and the longer roll pin.

Depress Pin of Trigger Guard
Depress Pin of Trigger Guard

Depress the pin of the trigger guard which will be closer to the magazine well.  Don’t worry, the two sides are differently sized so you can’t mess it up.  Then just slip it in.

One Side of Trigger Guard In
One Side of Trigger Guard In

Sometimes I find that the other side has a hard time dropping in so I lightly press down or even use the plastic hammer (lightly) if it’s slightly more stuck.

Roll Pin for Trigger Guard
Roll Pin for Trigger Guard

Make sure everything is lined up for the roll pin.

Start Roll Pin with Hammer
Start Roll Pin with Hammer

You can either start it with the hammer, with a punch or just with your fingers.  I like using the hammer to get started then using the C-Clamp below.  It’s much easier than trying to hold down the receiver while hammering.

Note: If you decide to go with just hammering…make sure you are supporting the dog ears or else they can pop off pretty easily even on a good quality lower.

Finish with C Clamp
Finish with C Clamp

I did end up marring my finish a little so I would heavily suggest using some plastic (I’ve heard a little piece of milk carton plastic between both sides of the clamp will do wonders).

Installed Trigger Guard
Installed Trigger Guard

The installed trigger guard.  You can see a little damage to the finish but I know I’ll be dealing a whole lot more damage to the receiver at the range and during competitions.

Bolt Catch Assembly

Bolt Catch Assembly Parts
Bolt Catch Assembly Parts

Find these parts!  The bolt catch spring is even throughout while the other remaining smaller spring is fat on one end for the disconnector.

Bolt Catch Spring and Plunger
Bolt Catch Spring and Plunger

Place the spring on the plunger and drop into the hole above the magazine latch.  There better not be comments on me needing a manicure…

Bolt Catch
Bolt Catch

Orient the bolt catch like above and drop it down.

Bolt Catch Roll Pin
Bolt Catch Roll Pin

You will need to depress the bolt catch for everything to line up.  I like using a hammer and punch to get it started.

Squeezing the Bolt Catch Pin
Squeezing the Bolt Catch Pin

Apparently, there’s a special tool to clamp the roll pin but I decided to make my own.  However, it wasn’t protective enough so I would suggest wrapping your pliers with tape first then some cloth.  Or you can just continue using the punch all the way through.

Installed Bolt Catch Pin
Installed Bolt Catch Pin

The finished bolt catch with just a little bit of marring.

That wasn’t so bad, right?  The trigger coming up is a little tricky but don’t worry, I got you!

Trigger Assembly

AR-15 Trigger Assembly Parts
AR-15 Trigger Assembly Parts

Pick out these parts from what’s left.

Correct Trigger Spring Orientation
Correct Trigger Spring Orientation

Attach the springs according to what you see above.

Disconnector Spring In Fat Side Down
Disconnector Spring In Fat Side Down

Place the fat side down into the trigger so that the spring stays put.

Disconnector Placement
Disconnector Placement

Place the disconnector onto the spring.

Trigger Hole
Trigger Hole

Press down on the disconnector to see the trigger hole.  You’ll be placing this assembly into the receiver and then putting a pin through it.

Placement of Trigger
Placement of Trigger

Place the assembly so that the trigger goes through the oval bottom of the receiver.

Trigger Hole Through Receiver
Trigger Hole Through Receiver

Matchup everything so that you can see the clear hole for the pin.

Trigger Pin Almost Through Receiver
Trigger Pin Almost Through Receiver

I sometimes find the trigger pin has some trouble once it’s almost through.  Sometimes I resort to using a brass punch after matching it up.

Installed First Trigger Pin
Installed First Trigger Pin

Here you see the fully installed first trigger pin.

Double-check the placement of the hammer and spring.  Make sure the springs lay on top of the first trigger pin.  They’ll be decent pressure to align the second trigger pin hole.

Trigger Hammer Pin Halfway
Trigger Hammer Pin Halfway

Once you get the trigger pin halfway through, I like cocking the hammer down so that it eases the pressure a little bit.

Trigger Hammer Pin with Punch
Trigger Hammer Pin with Punch

It turned out extra stiff so I used the brass punch.

Installed Trigger Hammer Cocked
Installed Trigger Hammer Cocked

Here’s the installed trigger assembly.

Release Trigger with Finger
Release Trigger with Finger

Resist the urge to dry fire!  You’ll release the hammer which has nothing to hit except the lower receiver.  Do this enough and it will start to damage it.  I hold the hammer down with my other hand so that it slowly releases instead of slamming into the receiver wall.

And there you have it…the trigger assembly!

Safety, Takedown Pin, Grip, & Receiver Extension

Still with me?  We’re in the home stretch now.

Safety, Takedown Pins, Grip, Receiver Extension
Safety, Takedown Pins, Grip, Receiver Extension

These should be the remaining parts in your kit.  Note the different sizes of springs relative to each other.  The two skinnier longer ones are identical for the takedown and pivot pins.

Grip Holes
Grip Holes

Let’s start with the grip.  The top one is a normal pistol grip while the bottom is the CA legal Hammerhead grip.  Both have holes for a screw and washer.  You might just need a longer hex key for the pistol grip to reach all the way in.

Cock Hammer Back
Cock Hammer Back

But first, let’s cock the hammer back so it opens up the safety selector hole.

Insert Safety Selector
Insert Safety Selector

Insert the safety selector.

Set Safety to Fire
Set Safety to Fire

Set the position to “Fire”

Safety Detent
Safety Detent

Find the safety detent (pointed side into the receiver) and put it in the hole on the opposite side of the safety indicator.

Safety Detent Inserted
Safety Detent Inserted

A much better view of the silver safety detent installed.

Spring for Safety Detent
Spring for Safety Detent

Find the safety detent spring.  It’s the thinner one that is slightly shorter than the other identical thin springs.

Insert Spring into Grip
Insert Spring into Grip

Insert it into the hole at the top of whatever grip you’re going to use.

Spreading Apart Hammerhead Grip
Spreading Apart Hammerhead Grip

Sometimes the grip doesn’t fit on easily (nor do you want it to be loose).  I find that using a big flathead makes it easier to slide onto the lower receiver.

Matching Up Spring with Safety Selector Hole
Matching Up Spring with Safety Selector Hole

Match up the spring with the safety selector hole and double-check that the safety selector is still in the “Fire” position on the opposite side.

Screwing in Grip
Screwing in Grip

Screw in the grip with the enclosed hex nut and washer.

Shorter Rear Takedown Pin
Shorter Rear Takedown Pin

Look for the shorter pin (rear takedown pin) which will have identical spring and detent to the longer pin (pivot pin).

Install Rear Takedown Pin and Detent
Install Rear Takedown Pin and Detent

Install the rear takedown pin from the left to right (shown fuzzily, sorry!) and also place the detent in the back of the receiver.  It helps to orient the takedown pin so its “channel” will accept the detent.

Insert Detent Spring
Insert Detent Spring

Insert the detent spring.

Buffer Retainer and Spring
Buffer Retainer and Spring

Now find the buffer retainer and spring (thickest one left) and place it in the hole above.

Placement of End Plate
Placement of End Plate

Also, take a look at your end place where one side has protrusions which will fit nicely with the back of the receiver.

Castle Nut First
Castle Nut First

But first, screw on the castle nut in the position above.  With the bigger square cuts toward the back of the lower receiver.

End Plate on Buffer Tube
End Plate on Buffer Tube

Then put on the end plate in the correct orientation.  I’ve definitely done this in the wrong order, so please learn from my fails!

Screwing in Buffer Tube
Screwing in Buffer Tube

Start screwing in the buffer tube.  The end plate will move with each turn and start messing with the spring.  Try your best to not let it come out.

Almost Done Screwing in Buffer Tube
Almost Done Screwing in Buffer Tube

When you’re almost done screwing in the buffer tube, take a break to look at the other side.

Buffer Tube Almost to Buffer Retainer
Buffer Tube Almost to Buffer Retainer

You want to stop right before the buffer tube reaches the buffer retainer.

Buffer Retainer Active
Buffer Retainer Active

Perfect fit with just a little bit more of a turn.

Match Up End Place
Match Up End Place

Now you need to match up the end plate with the receiver and also make sure that when the plate is tightened that it will hold the spring.

Screw in Castle Nut
Screw in Castle Nut

Start screwing in the castle nut with your hands first.

Tightening Castle Nut
Tightening Castle Nut

If you have an AR-15 armorer’s tool, it will have a section to tighten the square cuts.  I’d heavily recommend that since it’s only a few bucks.  But otherwise, you can also just lightly punch it tight.

Staked End Plate,
Staked End Plate,

You can also “stake” your castle nut where you use a center punch to smash in the end plate into the smaller cuts of the castle nut.  I would recommend testing out your lower a lot beforehand since it’s annoying to undo but really keeps it together.  Also, make sure your end plate allows staking.

Front Pivot Pin
Front Pivot Pin

Now find the last pin, screw, and detent that will be for the front pivot pin.

Detent Spring In
Detent Spring In

Place the detent spring in first.

Detent In
Detent In

Followed by the detent.

Pliers and Razor to Hold Detent
Pliers and Razor to Hold Detent

Time to whip out the pliers and utility knife to hold the pin down flush against the receiver since you’ll be sliding the pivot pin over.  I’d recommend doing this in a sideways cardboard box or something above you to catch the potential flying detent and spring if you mess up.  Also, you might want some eye protection.

Insert Front Pivot Pin
Insert Front Pivot Pin

Insert the front pivot pin over the knife blade with the channel facing where the detent will spring out.  This will install the pivot pin.

Completed Front Pivot Pin
Completed Front Pivot Pin


Stock, Buffer Spring, and Buffer
Stock, Buffer Spring, and Buffer

Now find your stock and buffer and buffer spring.  Yes, it’s super ugly but I got it since it was the cheapest “color.”

Buffer Spring In
Buffer Spring In

Insert the buffer spring in.

Buffer End Out
Buffer End Out

The buffer end will orient like the above.

Slide on Stock
Slide on Stock

Slide on the stock until it doesn’t move easily.

Pull Tab to Engage
Pull Tab to Engage

Pull the adjustment tab out and continue moving the stock inwards.  You can now use the adjustment tab to select your preferred distance.


Unless you’re in CA and want to pin your stock, then check out my How to Pin a Collapsible Stock Guide.

But if you’re like me…you want to make your AR-15 lower receiver the best it can be.  Here are the upgrades I added immediately and that I detail in my Ultimate 3-Gun Rifle Build article (coming soon).

Ultimate 3 Gun Rifle Build
Ultimate 3 Gun Rifle Build

AR-15 Lower Receiver Upgrades

AR-15 Lower Upgrades
AR-15 Lower Upgrades

JP Silent Captured Spring

One of the best upgrades to make your AR-15 feel like a pellet gun!  It takes away the *sproing* of the traditional buffer tube and drastically reduces recoil.  If you’re going with a lighter BCG, I’d recommend getting it with the additional springs so you can truly tune your gun.  Otherwise, the stock spring works great.  See my in-depth review here (coming soon).  Also available on JP’s official site.  And how to Install & Tune the JP Silent Captured Spring.

Slide in JP Silent Captured Spring
JP Silent Captured Spring

DPMS Ambidextrous Safety

Useful especially when you’re running a CA featureless rifle, but if you’re a lefty it’s critical.  The DPMS one is not the smoothest but for a little more you can get my favorite Battle Arms version.  How to Install Your Ambi Safety.

Screw in Ambi Safety
Screw in Ambi Safety

Magpul BAD Lever

On every single one of my lower receivers.  Makes manipulating the bolt super easy from your right hand.  Install it in less than 5 minutes.

Assembled BAD Lever
Assembled BAD Lever

Hiperfire Trigger

Swapping out the trigger is probably the best upgrade you can do to your AR-15.  This one is a new single-stage trigger that has no perceptible creep, little reset, adjustable weights (I run mine at the lightest 2.5lb), and actually increases the hammer strike power.  One of the weaknesses of other triggers is that while you can get light pulls, those sometimes can lead to light primer strikes too.  See my in-depth review.  The installation was also much easier than I expected given the number of parts.

Hiperfire Eclipse Trigger
Hiperfire Eclipse Trigger
Hipershoe Installed
Hiperfire Installed
Hiperfire Eclipse 2.5 lb Trigger Pull
Hiperfire Eclipse 2.5 lb Trigger Pull


There you have it…the complete visual guide to building your own AR-15 lower receiver!  Pair it up with our How to Build an AR-15 Upper Receiver and also check out the Definitive AR-15 Resource for even more upgrades, optics, etc.

Lots of AR-15 Uppers
Lots of AR-15 Uppers

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129 Leave a Reply

  • Rp

    Just used this on my first lower. Thanks for the guide. The hardest part overall was the trigger guard pin, followed by the upper takedown pin spring. I didn’t listen to your advice and ended up losing one but thankfully my parts kit had a spare. As a total noob the hammer orientation wasn’t clear to me so I had to fall back to a video to get that part working.

    May 14, 2021 9:11 pm
  • JK

    Awesome experience for me to have this kind of guide for a noob like me. Thank you very much.

    May 4, 2021 7:56 pm
  • george

    Does the trigger disconnector ever need to be filed down at the bottom to get the pin to go through if it does not line up with different receivers and different disconnectors?

    May 3, 2021 5:14 pm
    • Tim W

      No, it just needs to be lined up correctly which can be a pain.

      May 22, 2021 1:24 pm
  • Meph

    You just helped me put together my 1st ever lower receiver in 2 hours or less. This was absolutely great, thank you.

    April 26, 2021 5:48 pm
  • Nu

    great details on assembly the AR-15. I like the detail that you've provided step by step. Awesome work.

    April 24, 2021 11:53 am
  • Dan Koehler

    Thank you for giving complete instructions, that are understandable

    April 23, 2021 6:11 am
  • JM

    thaanks for the help.
    im a techy guy, but this was beyond my scope when it come to assembling a rifle.
    now i know how.

    April 13, 2021 12:56 pm
  • Frank

    the beat tutorial video

    March 31, 2021 1:18 pm
  • Martin

    Thanks, just completed my first lower. Not having the exact tools, I found a few things that helped. Built on an Anderson lower using an LBE lower kit. The biggest issue (probably for all) was the roll pins. I used a Vise Grip 5WR (5 inch) which is one of the smallest to hold the pins. I lined up the pins right on the edge and used my hammer to strike the Vise Grips to start the pins. Once everything was lined up, I used an Irwin 7 inch clamp. Great tool, Rubber coated jaws, but I removed the one against the roll pin. Since they are plastic, it did not mar the lower, but provided plenty of power to push the pins. Only other thing was installing the hammer. I lined up the holes and inserted a small punch which helped when setting the Hammer pin. Better than trying to push the hammer down with one hand and trying to set the pin.

    February 23, 2021 7:37 pm
  • Michael Higgins

    I've used this for 3 lowers. Works perfectly every time. USE a plastic hammer head. Thanks Eric!!!

    January 30, 2021 10:47 am
  • Enos Bacon

    Best step-by-step I’ve seen. Well written, fully inclusive, and insightful. Thank you for sharing. I highly recommend it to anyone looking to build an AR-15.

    January 3, 2021 3:18 pm
  • Steve From SC

    Great help! Just built my first AR pistol! Had a bugger of a time getting the hammer retainer pin through but not your fault. My only confusion was the install of the buffer retainer. It isn’t shown well in the photo and I had to look around a while and zoom in on a subsequent photo to see which way the pin cap went on the spring. But I did figure it out and it is obvious once you see how it goes. Now I plan to try it out tomorrow if there is a dry spell before or during the forecast rain. Thank you!

    December 30, 2020 5:54 pm
  • Jeff

    Great article! I just built my first lower using your instructions. My only suggestion would be to add some more detailed pictures on how to install the hammer, and how to poison the hammer spring inn side the lower. I had to search for a YouTube video to help me with that portion.

    November 21, 2020 9:58 am
  • Sean M Paterson

    Built my first AR15 pistol today using your DIY guide. Its a gift for my wife so it was really important that I didn't screw it up so I appreciate all the help and pictures provided. Thanks again. Its turned out great!

    October 4, 2020 11:46 am
  • George

    appreciate this article, was super helpful and accurate.

    September 13, 2020 10:19 pm
  • Mark

    Thanks for a great step by step lower build, I just finished 2 lowers and your instructions were spot on .

    September 8, 2020 4:37 pm
    • David, PPT Editor

      Awesome! Have fun shooting them :D

      September 8, 2020 4:40 pm
  • Matthew

    Just built my first AR-15 and the step by step instructions were great. Thank you for the information!

    August 29, 2020 7:59 am
  • James

    This was my first build and I went with an 80% Polymer lower so a few things were subtly different but overall went very smooth. A perfectly functional if cosmetically imperfect AR-15 with some great upgrades for 1/2 the cost of an over the counter unit. I was a little skeptical I'd be able to build one from scratch but I'm glad to say 2 months of methodical research, purchases and lots of time on this site has led to one of my better achievements. Cheers and thanks for all the helpful info. Keep up the good work.

    August 11, 2020 1:24 pm
  • Alex

    Thanks. All went well, only on trip to the gun shop for an extra spring. One had to run away.

    August 4, 2020 8:31 am
  • Doug

    No torque wrench needed for castle nut? Just snug it on tight with an armorer's wrench and be done with it, correct?

    May 15, 2020 7:05 am
    • Doug

      Also, I don't stake my castle nut either so is it really necessary to torque it to 40 ft. lbs. like some recommend?

      May 15, 2020 7:09 am
  • Jason

    Can you please email me the PDF so I may print the instructions without all of the internet adds?
    Thank you!!

    May 12, 2020 8:21 am
    • David, PPT Editor

      Our articles aren't available as PDFs, sorry.

      May 12, 2020 8:23 am
  • D

    I am about to assemble my first AR and this is such a helpful resource! The clear language and crisp photos make the task much less daunting!

    April 25, 2020 5:16 am
  • Max L

    Best step by step I’ve ever read/seen! Super useful, easy to understand steps, and very well taken pictures. Just about as good as having a friend walk you through it in person! Many thanks!

    April 18, 2020 5:03 pm
  • Jim Beck

    Thanks for your tutorial.
    I have built a few ARs over the years but, appreciate your input to avoid mistakes and "buggering" my receiver !

    April 8, 2020 11:56 am
  • Chris

    Thanks, Eric! You've been my go-to resource for all things AR since getting back into this a few months ago!

    April 5, 2020 3:29 pm
  • Brandon

    I used this article last weekend on my first lower receiver assembly.
    Your clarity was super helpful and I really enjoyed myself.
    The rifle performed wonderfully.

    March 16, 2020 2:52 am
  • Sal

    I used takedown detent on bolt catch because the youtube guys go so damn fast and don’t show shit clear ugh. This made it so clear gotta go to gun shop now. Thanks for being clear as day. Seriously I was like wtf is going on lol

    February 20, 2020 8:23 pm
  • Dan

    I used this guide to put together an AR15 lower from parts. Thanks for the help!

    February 14, 2020 9:00 pm
  • Jack

    When assembling and installing the trigger, disconnect and spring(s) it makes the job much easier if you use a temporary pin (which can be cut from an old drill bit), which will be driven out by the actual trigger pin during installation. That way you only have to line up the hole in the trigger with the one in the receiver instead of trying to line up holes in three pieces while fighting two springs.

    February 13, 2020 9:28 pm
  • William

    Wow !!’ That had to take a lot of time.
    Very helpful.
    Thank you for your continued great work.

    February 12, 2020 4:15 pm
  • Steve Shannon

    I assembled a lower using your instructions last night. It was very helpful to understand the order things needed to be done. Thank you very much!
    Three things that I noticed:
    You said: "Install the rear takedown pin from the left to right (shown fuzzily, sorry!) and also place the detent in the back of the receiver. "
    1. Just like the front takedown pin, the rear takedown pin goes from the right to left, not left to right.
    2. Don't put the detent or spring into the rear of the receiver yet. Instead, screw the buffer tube almost all the way in to the correct position, but with the castle nut backed off. Then, insert the detent pin, followed by the spring. Hold the spring down and rotate the buffer tube until the receiver plate covers the spring. That way you only have to hold the spring in place once, instead of each time the buffer tube and receiver plate go past. It makes it much easier.
    3. For the front takedown pin, use a small punch to compress the spring into its recess, then place the point of a safety pin or heavy straight pin through the hole in the side of the receiver. The pin will hold the spring in place while you drop in the detent making it really easy to start the front takedown pin. Once the front takedown pin is in place pull the straight pin out and rotate the front takedown pin until the detent snaps into place.

    January 29, 2020 3:47 pm
  • Porfirio Castro

    Great and concise guide, THANKS!

    January 21, 2020 7:30 pm
  • Mike

    This is a great guide, it made assembly of the two lowers I finished a snap. With one exception. The bolt catch pin installation. It's OK, but there is an easy way to do it using simple DIY tools. See Joe Pleczynski's method at

    The key is the bent wire tool that holds everything in place with the holes aligned. Anyone with wire and two sets of pliers can make it. The size doesn't even have to be very exact, Any solid wire between 1/16 and 3/32" diameter will work, the 3/32" being the perfect size

    You can get away without it, but if someone has finished the lower from an 80%, they know enough and have the tools needed to make his pin holding punch. But even without it, protecting the lower with masking tape and just getting the pin started holding with with needle nose pliers until it is in far enough to hold itself works OK. It is much easier and less risky for damages than the method you describe.

    Even so, this is probably the best and most comprehensive photo guide available. I did a lot of looking online before I started my assembly and there is a lot of great info, but its often fragmented. Yours is complete. Do a second edition with lubrication info, alternative methods for bolt catch and maybe pivot pin, maybe trouble shooting and it truly would be THE definitive guide to lower assembly. And I don't mean that in the usual hyperbolic sense but that it really could be a gold standard. You could probably even sell it as a print formatted pdf. Some of us still like to have a manual to lay out in front of us. Videos are nice at times, but a good photo guide is easier to get the big picture of how things go togethert and are better references for going at your own pace,

    Regardless, thank you for making this one. I was able to assemble with ease the components from PSA lower parts kits into two tactical machining 80% lowers I finished.

    January 20, 2020 1:28 pm
  • Joe Simone

    Great instructions and pictures went together real smooth thanks

    January 8, 2020 4:53 pm
  • Darren S.

    First time putting one together. Great instructions and pics - made it a snap.
    Thanks for sharing!

    December 29, 2019 3:28 pm
  • mike

    awesome! thank you!

    December 28, 2019 10:05 am
  • Sam Griffith

    First time builder along with my son (age 11), we had a blast! The instructions and pics led us through with no problems. Finished the lower and we are both looking forward to more. Until I acquire my upper, we will take down one of my other guns, oil it, reassemble and shoot with it. I think we found a new hobby to enjoy!

    December 1, 2019 11:16 pm
    • David, PPT Editor

      Awesome! Thanks for letting us know, always nice to read these kinds of stories :D

      December 2, 2019 3:28 am
  • David Acker

    Great write up with outstanding directions. Found a clever hack for the front pivot pin install on not long after my first build when the spring and pin went flying and I had to wait two days for parts ;-) Run down to your local hardware or big box store and buy a 1/4" clevis pin, the kind with holes, not the ball bearing type. Costs less than a dollar and works like a charm.

    November 29, 2019 9:44 pm
  • Allen Blevins

    Better to get a set of roll pin punches from Brownells instead of using the c clamp.

    November 27, 2019 5:15 pm
  • Rickey Holtsclaw

    Thank you for the step-by-step...excellent job and much appreciated. Get out of's too short!

    November 5, 2019 3:43 pm
  • Rich Fabsits

    Thanks for the great instructional. I could of put most of the darn thing in my sleep in the 70’s but was a challenge today especially with my fat fingers. Would of never made it without your tutorial. Just wanted to build an old M4 n PSA had a great little put together lower. Thanks again n I use a lot of your videos

    November 3, 2019 6:30 pm
  • Liberty Freedom

    Excellent writeup, I am about to do this myself and this is a million times better than watching an hour-long youtube video.

    Which featureless grip is that on your gun and how do you like it compared to the Thordsen stocks? I'd rather pin my stock and use that grip than buy a featureless on my next AR15 so it looks better and is cheaper to build.

    Thanks again

    September 22, 2019 8:31 am
    • David, PPT Editor

      Eric used the Hammerhead grip for this article, I like featureless grips and a pinned stock a lot better than the Thordsen stocks. They are easier to install and uninstall, give more options, and look a lot less...featureless.

      We have a complete review of a huge range of Featureless Grips that you'll want to take a look at! Personally, I like the Resurgent Arms and Strike Industries Megafin best.

      September 22, 2019 9:01 am
      • Liberty Freedom

        Thanks! Finally got my lower out of jail and am assembling it now. It's just like legos with your guide. I ended up going with the Sparrow Dynamics grip, it looks pretty similar to the Resurgent Arms grip on the featureless grips guide.

        November 12, 2019 10:59 pm
  • Fritz Heinrichs

    Wonderful assembly guide, with awesome pictures which made the steps easy to follow.

    One thing folks might want to consider when installing the front pivot pin is the trick using a 1/4" Clevis pin and something narrow enough to compress the detent spring (youtube video on this here - You should be able to find Clevis pins cheap at a local hardware store.

    September 21, 2019 11:36 am
    • cathammer

      Definitely the way to go. I had some one-hole aluminum clevis pins left over from an old external frame backpack, and made an insertion "punch" from a piece of coat-hanger with a loop on one end that I could leave attached to the clevis by its split ring when not in use, and have the whole little kit all together. Not pretty, but works fine.

      Actually, if you have a piece of 1/4" aluminum or brass bar handy, or even a wooden dowel, you can also easily make your own pin if you can drill a hole.

      October 10, 2019 9:39 am
  • Ben

    Thanks! Great job! Perfectly walked me through assembling my first AR.

    August 23, 2019 7:37 pm
    • David, PPT Editor

      Glad we could help!

      August 24, 2019 3:00 am
  • Chuck Sellers

    Thanks. Good article.

    July 27, 2019 5:30 pm
  • Ron Peterson

    do you have video of how to change the AR9 buffer tube to a stock AR15 buffer tube assembly and adjustable stock ?

    July 18, 2019 5:40 am
    • David, PPT Editor

      AR9 and AR-15 should use the same buffer tube, but the weight might differ depending on your AR9 setup.

      July 18, 2019 4:27 pm
  • paul sniffen

    great job, well done

    June 22, 2019 5:42 pm
  • BravoAlphaGulf

    Thank you. Just finished a project. I did not say that. I am not here

    June 5, 2019 8:22 pm
  • Joshua

    Definitely appreciate the step by step. It was a great write up. Some of the steps could use a "this is how you know it was done right" kind of thing if you are ever considering a version 2.0. But thanks again!

    May 5, 2019 9:44 am

    Thank you! Very detailed and informative. Lucky for me I had a drop in trigger so it made it alot easier.

    April 26, 2019 4:48 pm
  • Dane Van Allen

    I die a little inside every time I see a featureless grip on this site

    April 1, 2019 8:34 am
  • Bella

    Great write up!!

    March 20, 2019 1:51 am
  • neal perez

    wish you had PDF File of article, love it great photos and detail

    March 18, 2019 5:51 am
  • Mac

    Thanks, great write up, Eric! Super set of pics, everything a builder needs.

    Boy that CA hammerhead grip is ... unfortunate. Yeesh.

    You can avoid aggravation—and a frustrating bent or lost spring—by waiting to insert the rear takedown pin, detent, and spring until the last 1/4 turn of the buffer tube / end plate screw on step. You can use the razor trick there, too.

    March 14, 2019 7:03 pm
  • Rich Bowman

    Thanx for the build directions, Bradda! AWESOME!

    March 5, 2019 7:58 pm
  • Unchained

    Did a 308 lower with ease because of your tutorial. Good details and pics. Great job dude, thanks.

    January 25, 2019 8:10 pm
  • Supremeblt

    What type of oil/grease do you use during assembly?

    January 25, 2019 7:02 am
  • Dan

    Just used your instructions to put together my first AR. Great job. Couldn't have been easier. Thanks!

    January 24, 2019 7:06 pm
  • Dom

    Just put together my first lower. Your instructions made it super simple. Thank you for the help. Keep up the awesomw work. God bless.

    January 22, 2019 12:54 pm
  • Dirk Diggler

    Two corrections: "Install the rear takedown pin from the left to right" is backwards. Pin goes right to left. Second, there are various instances of "end place" instead of "end plate."

    Thanks for the great content.

    December 27, 2018 12:53 pm
  • Mike

    Built my first ever multi-caliber Anderson lower. I used the Anderson build kit with the 440 stainless-steel trigger. Your instructions and photo layout made it very easy to complete my lower.

    December 14, 2018 8:42 pm
    • David, PPT Editor

      Awesome! Glad we could help. Have fun!

      December 15, 2018 6:27 am
  • Steve AZ

    Eric! You rock! First AR lower build (Anderson). Your step by step instructions made it almost too easy. Thanks for this and all your reviews. Read them regularly.

    December 14, 2018 1:36 am
    • Eric Hung

      You're so welcome, Steve!

      December 27, 2018 5:07 pm
  • Todd

    Thanks for the great instructions! I had no problems setting roll pins using an old diesel generator trick when putting the giant nuts and bolts together. The day before, I put the pins in the freezer (still in the plastic bag to prevent inducing moisture, though 1 day shouldn't be an issue). It shrinks the metal enough that they were snug, but I had no problems at all.

    December 7, 2018 7:09 am
  • Sean WA

    Great instructions fellas! First build tonight with a PSA 5.56 NATO 10.5" pistol kit with Magpul grip, PSA lightweight 10" MLOK handguard, and SBA3 brace. Machined two 80% lowers earlier in the day. BEAUTIFUL pistol! Your directions were spot on and the only trouble I had was when I temporarily lost the buffer retainer and spring (Yep, I backed the buffer tube off and forgot too watch the retainer)! Thanks for the great instructions. Made the job easy. Cant wait to get out and get it on the range. One more build to put together sometime in the next few days, but it will be even easier than this one I'm sure.

    Side note, Pew Pew Tactical is an every day must read now. Thanks for all of the great advice and reviews.

    November 14, 2018 9:35 pm
    • Eric Hung

      Hi Sean, so glad we could help out!

      November 14, 2018 10:42 pm
  • Eric TX

    That was my first lower build and you made it a breeze! Everything works great and I owe it all to you Mr. Hung! I'm very impressed how easy it was with your instruction and pics. Thanks a lot, always reading all your reviews which I really value.

    October 5, 2018 10:32 pm
    • Eric Hung

      So glad we could help out!!

      October 6, 2018 12:40 am
  • Caleb Brown

    gotten to everything no problem up to the hammer. trying to get the pin into through to hold it in place but the J Hook is in the path of the pin and wont let it go all the way through. how do i fix this problem?

    June 1, 2018 5:14 pm
  • Ron F

    Just put together my first lower (Anderson), used your pics. Slightly different order as I did a rifle stock with a Luth MBA-1 and a Rock River National Match 2 stage trigger. All went well, didn't time it as I did it slow and easy. Did notice what you said on a couple didn't match the pics, I went with the pics!! But Thanks.
    Now waiting for my 22" Radical .224 Valkyrie upper from Primary Arms. Bought the lower local for $50, most everything else from Primary. All shipped correctly and fairly fast considering I went with cheapest shipping.

    June 1, 2018 2:23 pm
  • harvey

    I need some help.... Looking for any suggestions. I mistook the buffer assembly spring for the bolt catch assembly spring, rushing and wasn't paying enough attention (first build give me some slack). I was overeager and well she's in there good. seems like theres a lip keeping it in there. Any thoughts on how to get that out of there? I hope I haven't wrecked my build entirely. This is such a frustrating situation.

    May 21, 2018 4:34 pm
    • David

      Very small pliers or a dental hook. Rip the spring out, don't try to save it. Just get it out. New spring will cost you a dollar.

      May 21, 2018 5:06 pm
      • harvey

        Thanks David, I was thinking the same. I don't care if it is salvageable I just want it out. I already priced a replacement, no issue buying one. I was thinking of filling the port with some olive oil or something to help ease it out. Might do the trick. So frustrating, lesson learned for sure.

        May 21, 2018 5:15 pm
        • David

          Oil might help but I don't think it will, your problem isn't so much friction as just X is larger than Y.

          If you go with an oil use something with a lower viscosity than olive oil, Remington Oil would be my pick if you have it.

          Good luck!

          May 21, 2018 5:27 pm
          • Harvey

            David, problem solved. Used some CLP, and a drywall screw. teeth on the Drywall screw grabbed the spring when lightly threaded. Pulled it right out! Again thanks for the info!

            May 22, 2018 9:36 pm
          • David

            Awesome! Glad it worked out mate.

            May 22, 2018 11:35 pm
  • Patrick

    Excellent job guys! I used this today while assembling my first lower and I never had to leave the page! Thanks for all your help and information!!

    May 1, 2018 3:37 pm
    • David

      Glad it helped! Always good to know when we've helped a new AR builder finish their first one!

      May 1, 2018 3:40 pm
  • MxC

    Great tutorial! Just finished a pistol 458 socom, couldn't have done without your tutorial. I do recommend a drop in trigger though.

    April 18, 2018 11:04 am
  • Tracy

    Thanks for the tutorial. Great pictures. Easy to follow. Took less than 20 minutes on the first build. Keep up the great work.

    March 23, 2018 9:12 pm
  • Mark

    First AR15 build. Your steps were easy to follow and straight. I had about 6 hours into it and looks really good. Thank you for the step by step.

    March 18, 2018 4:21 pm
    • Eric Hung

      You're so welcome, Mark.

      March 26, 2018 3:15 pm
  • Claude

    P:robably the best lighting and camera work on AR15 build.

    February 21, 2018 2:52 am
    • Eric Hung

      Thanks Claude!

      February 21, 2018 11:16 am
  • Claude

    Probably the best lighting and camera work in any UTube videos on AR15 build.

    February 21, 2018 2:51 am
  • Todd Hanson

    Your Trigger Hammer spring is on backwards in the picture

    January 8, 2018 12:49 pm
  • Henry

    Thanks for posting this! I hate roll pins ;)

    December 29, 2017 2:00 pm
  • Terry Howard

    Just finished my build this was a great guide. Thanks

    October 29, 2017 8:44 am
  • Jeff Thalin

    Would you please talk about lubrication?
    How do you feel about pre-lubing the parts for protection before assembly?
    What parts do you feel require lubrication?

    October 4, 2017 4:48 am
    • Eric Hung

      I clean the parts to get preservatives off, and put a super light film of oil over the parts before assembly.

      October 4, 2017 3:14 pm
  • Steve

    First ever lower build and it was done in under thirty minutes! Thanks for a great guide!

    September 7, 2017 3:54 pm
    • Eric Hung

      You're so welcome, Steve!

      September 14, 2017 10:15 am
  • mike turbo

    just finished my first custom build, and thanks to you and your site it went flawlessly.

    much respect and appreciation.

    August 13, 2017 2:37 pm
    • Eric Hung

      Thanks so much Mike!

      August 17, 2017 2:32 pm
  • Vincent

    Great instructions. Used this from start to finish and didn't scratch the gun at all. Was a lot of fun and gives you the knowledge to find problems later on. Thank you.

    July 31, 2017 3:33 pm
    • Eric Hung

      You're so welcome Vincent!!

      August 6, 2017 2:05 pm
  • George Chapman

    I really like your site. I have downloads the Upper and Lower build and am going back over boat to see if I need to download more info from each area, I am a beginner, I have done some trigger installs and other things using You tube and that has worked for me in the past. I like your and will use it later on a 14.5 inch barrel build I am planning.

    July 4, 2017 1:21 pm
  • Roe Arnold

    Very nice presentation of the work being done. Simple,easy to understand. Thanks for your work

    June 25, 2017 12:11 am
    • Eric Hung

      You're welcome Roe!

      June 26, 2017 1:54 pm
  • JT

    Great job man, this is my go to.. I know how to build after 5 builds but always open this page for the brain farts. Thanks for taking the time to lay this out for all to access.

    June 23, 2017 9:26 pm
    • Eric Hung

      You're so welcome!

      June 26, 2017 1:53 pm
  • Dwight

    I didn't do as good a job as Jim, above, don't work well on my lap.

    Took it out to my leather shop, . . . put it on the table, . . . 90 minutes later it was good to go. Made one mistake, didn't screw the stock on far enough, lost the spring for the buffer stop.

    But all in all, . . . thank you for a wonderful and very informative video. Made my "first lower" very easy, . . . and only a half dozen scratches (that's good for me), . . . lol.

    May God bless,

    June 16, 2017 1:16 pm
    • Eric Hung

      You're welcome Dwight...and we all have some dings/scratches on our first...or even 10th.

      June 21, 2017 2:43 pm
  • Jim

    Excellent presentation. I read it all, dumped out parts and followed along. I did it in my lap with no special tools. It functions well and zero scratches. (Anderson lower and parts kit)

    June 8, 2017 10:48 am


    May 19, 2017 10:48 am
    • Eric Hung

      Glad we could have helped!

      June 5, 2017 12:51 pm
  • Felix

    Just finished my third build. I didn't think I could build an AR, I always thought it would be super complicated. But after doing alot of research online and finding PewPew Tactical. It became very easy.

    Thanks alot. This is definitely my go to place for all my future builds.

    May 2, 2017 7:37 pm
    • Eric Hung

      So welcome Felix!

      June 5, 2017 12:37 pm
  • Brian.

    Tons of experience with the M4 / AR 15 platform. Never build one. Your instructions made my build quick and easy. Thanks keep up the good work.

    April 15, 2017 8:35 pm
    • Eric Hung

      Thanks so much Brian!

      June 5, 2017 12:20 pm
  • Shaun

    Thank you for the awesome how to, I just finished my first lower, easy to follow and understand.

    April 1, 2017 5:19 pm
  • Paul

    Very useful, and helped me put together my first lower. However, there is a mistake. The hammer spring is installed correct in the "Correct Trigger Spring Orientation" photo, but then you flipped it on "Orientation of Trigger Hammer". I had my spring according to the second picture and the disconnector wouldn't release the hammer when letting off the trigger. Flipped it around and now it works perfect.

    March 31, 2017 6:46 pm
  • Mike

    Just finished assembling my AR lower using your photos. I've lots of experience shooting and field stripping AR's, but never assembled one completely. It was very simple thanks to your photos.


    February 20, 2017 11:41 am
    • Eric Hung

      You're welcome, Mike, glad I could help out!

      February 21, 2017 1:21 pm
      • Tom

        I recently had an issue with the buffer retainer. Removing and replacing it was simple. My question is, the retainer doesn't move like I thought it should, and the buffer spring pops just does what it wants. So, should the retainer move up and down? Having feed problems, jams, etc. The bolt no longer locks open. Any info is appreciated.

        July 6, 2017 9:27 pm
        • Eric Hung

          Hey Tom, I'll try to help but you might want to get it looked at by a gunsmith. The retainer should stay up to keep the buffer/spring from flying out, but be able to be pushed down whenever you want to manually remove the buffer/spring.

          July 7, 2017 2:52 pm
  • Tim

    Why would you put a "featureless" hand grip to make a compliant rifle but then use a collapsible stock which makes it non compliant?

    November 28, 2016 2:49 pm
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