How to Assemble an AR15 Instructions

[KnobCreek]

I know there are a lot of good instructions on how to assemble an AR15 already out there, but I thought it’d be nice if one of our own members provided some instructions as well…besides, I was bored and I had the time in between me looking for a job.
I received three Double Star lowers today and decided to snap off a couple pictures as I was going about assembling them. What normally takes about 30 minutes, took me 2 hours today, mainly because I had to set things up to take the pictures, position my fingers and parts so that I could snap off some clear shots, and drinking a couple cans of beer kindda impaired my vision.
OK, here goes…
Tools

There are a few tools that help facilitate in putting together these kits, but none of them are absolutely necessary. Minimum requirements include a hammer and punch to drive in a couple of roll pins, a flat-blade screwdriver for the stock screw, and either a screwdriver or Allen key for the pistol grip screw.
Roll Pin Punches - to drive roll pins (3/32", 1/8", 5/32"); these have a small raised projection in the face of the punch to automatically center the punch and prevent the roll pin from collapsing
Hammer - used to drive the roll pins
#10 Flat-Blade Screwdriver - used for A2 stock screw and some pistol grips
Block of wood - base to support receiver when driving roll pins
Allen Key - used for some pistol grips
Telescoping Stock Wrench - to tighten telescoping stock lock ringThe Parts

The lower receiver parts kit contains 30 parts not counting the stock assembly, the receiver, or the pistol grip. Most of these parts are covered in oil to prevent rust; wipe all the excess oil off before assembly. The following is a diagram of the parts that come in an LPK:
http://img.photobucket.com/albums/v82/knobcreek/lowerKit.gif






SPRINGS
Bolt Catch Spring - easily confused with the disconnector spring; disconnector spring is tapered though.
Buffer Retainer Spring - second largest spring in the kit.
Disconnector Spring - similar to bolt-catch spring, but identifiable because one end is wide than the other.
Hammer Spring - larger of the two similar springs.
Magazine Catch Spring - this is the largest spring in the kit.
Pivot Detent Spring - same as the takedown detent spring, so there are two in a kit.
Selector Spring - similar to the takedown and pivot detent springs, but there will only be one of these.
Takedown Detent Spring - same as the pivot detent spring, so there are two in a kit.
Trigger Spring - the smaller of the two similar springs.PINS
Bolt Catch Buffer
Bolt Catch Roll Pin - smaller of the two roll pins.
Hammer Pin - same as trigger pin; can be inserted from either side.
Pivot Detent - same as takedown detent; both sides usually rounded.
Pivot Pin - larger of the two large pins.
Selector Detent - one end is flat, the other pointed.
Takedown Detent - same as pivot detent; both sides usually rounded.
Takedown Pin - smaller of the two large pins.
Trigger Guard Roll Pin - larger of the two roll pins.
Trigger Pin - same as hammer pin; can be inserted from either side.
Bolt Catch
Buffer Retainer
Disconnector
Hammer - will have a J-pin already installed.
Magazine Catch
Magazine Catch Button - some are plastic, some metal.
Pistol Grip Lock Washer
Pistol Grip Screw - some are Allen-head, some use a slotted pan-head screw
Selector
Trigger
Trigger Guard - some are metal, some plastic. Will already have a detent installed on its front end.Assembly

Here are the steps that I normally follow when assembling an AR.
First, open up a can of your favorite brewskie. I’m partial to Killian’s Red, but I only had Miller Genuine Draft, so I had to make due with what was on hand.
You want to always work in a well-lit area, and it is helpful to work on a flat, hard and light colored surface. There are many small pins and springs, and they have a tendency to roll or fly away and disappear forever. Layout your parts and try and identify them. The springs look very similar, but have slight differences that make it important to not mix them up.
Here are the tools that I shall be using:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1335.jpg
This is the parts kit, upper and lower, that I shall be assembling:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1336.jpg
And these are the lowers that just came in, one of which, will be used in this instruction:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1339-1.jpg

I normally begin with the magazine catch assembly:
These are the parts you’ll be working with:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1340.jpg




Install magazine catch into recess on left of receiver then Install spring onto threaded portion of magazine catch from the right side of receiver. Screw button onto threaded portion of magazine catch 3 or 4 turns.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1344.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1341.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1342.jpg
You can use a punch (larger than hole in magazine button) or wooden dowel to push in the magazine button so you can turn the magazine catch clockwise until the end of the catch is flush with the magazine button head, but I just use a plastic safety chamber flag.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1343.jpg



Bolt Catch Assembly:
Next, I do the bolt catch assembly. Here are the parts you’ll be working with:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1345.jpg
When installing the bolt catch, first drive the roll pin about halfway into the rear hump from the rear of the receiver. I used an old credit card to protect the receiver’s finish while using a punch and hammer.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1349-1.jpg

Install spring and bolt catch plunger (on top of spring and small end into the receiver) in hole on left side of receiver.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1346.jpg
Install bolt catch in receiver; it only fits on one way and then the pin can be driven the rest of the way
http://img.photobucket.com/albums/v82/knobcreek/IMG_1351.jpg



Next is the trigger guard assembly
Plain and simple:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1352.jpg
Make sure you properly support the bottom flange of the receiver by laying the receiver on a block of wood. If you don’t, that flange will definitely break right off. Drive roll pin into receiver and rear of trigger guard using drive pin punch.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1353.jpg






The next step is installing the front pivot pin
These are the parts you’ll be using:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1356.jpg
Insert spring and detent into receiver:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1359.jpg
This is perhaps the hardest part of the lower assembly, so if available, use a pivot pin installation tool.


I just used a punch to help keep the spring and detent pin down while I slapped on the pivot pin:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1360.jpg
And here is the pin installed:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1361.jpg


The next step I do is the trigger assembly.
These are the parts you’ll be working with:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1354.jpg

This is how the parts should look once you installed the springs:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1355.jpg


Shoulder trigger spring onto trigger with ends of spring forward and under. Install disconnector spring with the wider portion of spring down towards trigger and push until it locks in there. Position disconnector on top of trigger, where trigger pin will hold both in place. Insert trigger assembly into receiver.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1362.jpg
I use another push pin to help with alignment while I insert the trigger retaining pin through receiver, trigger, and disconnector.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1363.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1364.jpg
Install trigger and use the same method to install hammer pin:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1367.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1368.jpg

Next assembly is the selector switch

These are the parts you’ll be using:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1369.jpg

With the hammer cocked back, insert from left side of receiver, selector pointing up in the 'fire' position.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1370.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1371.jpg


The following is part of the selector switch assembly, but pertains to the pistol grip assembly as well..
Insert detent detent, pointed end towards the selector, and the spring into the receiver from the bottom.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1372.jpg
Carefully compress the spring with the grip and make sure spring fits into hole in grip.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1373.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1374.jpg
Use the screw and lock washer to secure the pistol grip to the receiver:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1375.jpg





These parts should be the last in your pile:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1376.jpg

We shall be using them to install the collapsible buttstock and the rear retaining pin.
Install detent/spring into receiver:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1377.jpg
Install buffer retainer and spring:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1378.jpg
These are the parts for the collapsible stock assembly:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1379.jpg
Install buffer tube, backplate, and locking ring onto receiver and depress retainer when necessary to get it to rest under the extension tube. Turn tube until it is about 1/4 turn past the correct location.
http://img.photobucket.com/albums/v82/knobcreek/IMG_1381.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1382.jpg
Use a stock wrench to tighten everything up:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1383.jpg
You can stake the locking ring to the backplate if you so desire:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1384.jpg
And round the corner and heading home, this is the completed lower:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1385.jpg

Just mount a favorite upper, and go shoot:
http://img.photobucket.com/albums/v82/knobcreek/IMG_1386.jpg
http://img.photobucket.com/albums/v82/knobcreek/IMG_1387.jpg

Last step is to open up another brewskie and smoke a cigarette.

[okie shooter]

Don' know if I will ever build one my self, but I have two and need to do some work on change out of some parts, Thanks for the nicely done instruction set. It is much less intimidateing when there are good pictures with them too.

P.S. sounds like your last comment gets all the bases covered, by the alphabet guys, too.

[KnobCreek]

Yeah, I was very intimidated my first time around. I find that it helps if someone shows you the first time around, but since we can't always do this, the next best thing is to show someone using pictures....

[KnobCreek]

BTW, I've got 2 more receivers to do today and I lost track of how many more that are on back ordered via various vendors. That's OK, it should give me time to purchase more uppers.

The next instruction I want to document is building an upper from stripped parts.

[New2HKinAZ]

Can I add a couple tools I thought were also helpful during an AR15 build, although they aren't required?

One is the DPMS receiver claw found here: http://www.dpmsinc.com/store/products/?prod=1675. It allowed me to install a Larue FF tube without having to make that ugly action block mod you see on barfcom. It was pretty sturdy and held up through removing and torquing down a barrel nut.

Another one is this brass hammer and punch set found here: http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=973259. The soft brass didn't mark up the finish on my AR like a steel punch would if I slipped.

[97th Signalman]

That is a great instrucional sequence. If the Webmaster has a setup for stickies or permenant technical resources it should go there.

[kpd007]

Great work Knobcreek. This is a very good tutorial and just as good as others I have seen in other places. Thank you.

[Alaskagrown]

you didn't use all of those tools...

so when are you gonna show us how to assemble the upper?

[Smokehouse69]

It's been a while since I assembled an AR, about 29 years. I guess I'm gonna have to buy myself one so I can get some practice!!

[KnobCreek]

you didn't use all of those tools...

so when are you gonna show us how to assemble the upper?

Well, I have a complete upper and a fluted barrel, I'm just waiting on receiving my delta ring assembly, gas tube, barrel nut and a couple other things. I was hoping to begin with a stripped upper, but can do that some other time.

Yeah, I didn't use all the tools; I just wanted to take a picture of what I use for a complete build from stipped parts.

[bullseye]

Great, a dealer I like has receivers and parts its I was thinking about but told myself I couldn't do it. Now you have proven me wrong. My wife is gonna be mad. :) Thanks for the great tutorial, this is gonna be fun.

[arnaiz]

I dont like rear pin spring interfering stock changing, so I tapped the hole with 2,5 mm tap and after cutting spring instaled an allen screw with no head in the lower, So you can change stock and no bother with this spring.
What about pics of the upper.??

[LCPL 4]

Miller??? That just ruined the whole thread for me. I can taste a slight puke sensation building up in my mouth just thinking about it. Please tell me the brother-in-law left it in the fridge from the last visit or somethin.

Coors Golden Baby. Good enuff for the Bandit, It's good enuff for me!

[gunbunny]

Thanks Knobby...great pics!

So I'm gonna tell the wife it is YOUR fault that all these parts are all over her kitchen table.

[GearShanty]

Thanks Knobby...great pics!

So I'm gonna tell the wife it is YOUR fault that all these parts are all over her kitchen table.

I hope your wife's response to that is better than my wife's coming home to find an old M44 in the dishwasher.

[KnobCreek]

I hope your wife's response to that is better than my wife's coming home to find an old M44 in the dishwasher.

LOL, yeah, been there, done that. Surprised that she hasn't made me purchase my very own dishwasher yet.

[KnobCreek]

Miller??? That just ruined the whole thread for me. I can taste a slight puke sensation building up in my mouth just thinking about it. Please tell me the brother-in-law left it in the fridge from the last visit or somethin.

Coors Golden Baby. Good enuff for the Bandit, It's good enuff for me!

I'm a Killian's Red person, but it was all that I had in the fridge at the time....

[Alaskagrown]

KC - What LPK do you recomend?

[LCPL 4]

Builders guide in PDf I found on the net...

http://hosted.filefront.com/JE3146/

[amd65]

Good timing, Charlie. I just ordered my lower from Kiser, and have the rest of the parts coming, as well.

[Old Jimmy]

Thanks Knob Creek, It took me an hour and a half { lol }but I got my first one done. Thanks for the lesson,
Old Jimmy

[Planning]

knob, very good information. thanks. i only put one together every now & then. this will work as a very good reminder. very good pictures also.

[Phirebug]

has this been up here the whole time? i found this thread on a google search while i was looking for some instructions. i've got some in one of my gun books, but there's no pictures. i was getting a headache trying to figure out the pivot pins from the text-only instructions. thanks knobby!!

oh...you gotta get rid of that miller, buddy.

[KnobCreek]

oh...you gotta get rid of that miller, buddy.

I'm normally a dark ale person, but it was the only thing left in the fridge at the time. :wink:

[Phirebug]

that doesn't mean i'm not gonna tease you about it. ;) honestly though, i'd walk ten miles for a cold miller right now. hell, probably even a warm one.

seriously though, those are some great instructions. i've already got this thread bookmarked for my build in a couple months. thanks for putting this together.

[ctdemolay0405]

if i buy a lower and an upper seperately, should everything be there that i need, or is there other stuff i would need to buy. sometimes it looks like its cheaper to buy a lower and an upper seperatly then install them together... is that a good way to do it?

[LCPL 4]

If buying an upper just make sure it includes the bolt and bolt carrier. You may find one that seems like a good deal but some places/people sell them without.

Alot of people use Del-ton for kits. For example, you could purchase a kit from this page -

http://www.del-ton.com/AR_15_Rifle_Kits_16_s/57.htm

Then all you need is a lower for about $100 + ffl fee. A few hands tools as described in instructions and you should be good to go. many other companies that sell kits, complete uppers, etc. Just have to shop around. Or you could shop around for used parts on the various forums and try and make one on the cheap side.

[KnobCreek]

if i buy a lower and an upper seperately, should everything be there that i need, or is there other stuff i would need to buy. sometimes it looks like its cheaper to buy a lower and an upper seperatly then install them together... is that a good way to do it?

Normally, a complete upper kit will include a bolt, carrier, charging handle and everything needed to assemble a lower. Best thing to do is to verify with the vendor that you chose to do business with. As mentioned above, Del-ton is a very good source to find basically everything you'll need to assemble a rifle.

[ctdemolay0405]

i'll look into it. maybe i'll just build like in this thread, theres gotta be some satisfaction to shooting something after u put alot of time and effort into building it.

i dont have to worry about milling or any other adjustment of these parts from the kits right?

[KnobCreek]

Actually, it doesn't take that much time at all; I can get one assembled in less than 30 minutes. As for milling and any other adjustments, you shouldn't have to do anything with the parts; they should just assemble together just fine.

[cfish]

Hey Knob whos parts kit did you use to assemble the lower?

[KnobCreek]

I've been exclusively using Rock River Arms' lower parts kits since I haven't had any issues, but you can use other vendors' with much the same luck.

[brussell1976]

knobcreek, Great job ! One of the clearest instructions i've ever seen for doing a AR build. Your post would be very helpful for any beginner doing it for the first time. When I built my first ones a few years back, I always struggled with the front pivot pin and spring (springing it across the room, then spending time looking for it hidden in the carpet). I finally figured out your method (of putting a punch thru the other side to hold it in place). Your post would have saved me tons of headaches! Thanks

[rudrules]

Great instructions! now I have a better understanding of my AR.
Thanks for your post and great pictures, i'm going to save them for later if you know what I mean.

[ctdemolay0405]

I built my lower 2 days ago (no pics yet) and it was easier than i thought... considering i've never done anything like it before. done in 20 min. i'll do it again no problem. no matter how many times i read the directions and watched the assembly videos i've found, etc..... i'm still nervous that i f-ed up. everything function checks correct according to the build directions.... but still..... then again, i've never built an AR, or field stripped or anything, just shot a few times.....


now i just continue the waiting game on the upper

[landtoy80]

Brownells has a great build video. I just used it yesterday to build my lower.

http://www.ar15builder.com/
Look at the bottom for the videos.

[cz777]

two roll pins -bolt catch and trigger guard both have broken many lowers ! i use a drill to hold the pin and use a file ,turn down the edge of the pin app.45 angle,what goes in first also use oil on pin too .....

[ctdemolay0405]

two roll pins -bolt catch and trigger guard both have broken many lowers ! i use a drill to hold the pin and use a file ,turn down the edge of the pin app.45 angle,what goes in first also use oil on pin too .....
not to be a jerk, but i dont understand a damn thing you said.

as far as broken lowers and the trigger guard, you MUST support the ears while driving in the roll pin. I used a block of wood on my first build and will use something similar on my second when the butt stock assembly finally comes in. if you have the ears supported, there should be no problem

as far as driving in the pin to hold in the bolt catch, there should be no problem if you are using the correct roll pins. the bolt catch can even be put in using channel locks/vice grips with tape over the faces so you don't mar up the finish on your lower.

i'd say if the pins don't go in fairly easy, the pins might not be the right size

[ackspac]

not to be a jerk, but i dont understand a damn thing you said.

as far as broken lowers and the trigger guard, you MUST support the ears while driving in the roll pin. I used a block of wood on my first build and will use something similar on my second when the butt stock assembly finally comes in. if you have the ears supported, there should be no problem

as far as driving in the pin to hold in the bolt catch, there should be no problem if you are using the correct roll pins. the bolt catch can even be put in using channel locks/vice grips with tape over the faces so you don't mar up the finish on your lower.

i'd say if the pins don't go in fairly easy, the pins might not be the right size

+1. The only way I could see breaking your lower is by not using a block of wood while installing the trigger guard. There are a bunch of videos on YouTube and such that go into great detail on every thing about building an AR. Good luck.

[cz777]

[QUOTE=ctdemolay0405;156391]not to be a jerk, but i dont understand a damn thing you said.sorry

you MUST support the ears while driving in the roll pin ...YES . i use a drill to put a taper/chamfer on the roll pin[right ones] with a file and some eezox on the pin and hole of receiver ,to help the start the pin ...... this helps