Building an AR-15--what do I need to know?

[Recluse]

I get a phone call from the SIL telling me that he was recently given a complete lower receiver for an AR-15 and wanting to know if I'll help him build the rest of it. I tell him sure but that I'll have to get some advice and counsel from people far wiser than me on the matters of black guns. He knows how I feel about black guns but sees this as an opportunity.

Went scouring around the internet looking at information and it is mind-boggling.

Anyone who's built on of these things, what do I need to know and what advice or recommendations would you have?

Thanks.

:coffee:

[popper]

Try for a full upper that fits. Good luck finding parts. You will need the upper vice block, torque & spanner wrench, roll pin tools, etc. No biggie except finding a bolt that sets HS correctly. I'd find someone to do a complete checkout of the lower before I put much into it.

[AggieEE]

Well as one Texan to another the simpliest approach would be to buy a complete upper, CMMG, Dainal Defense and Rock River Arms are some that come to mind and I'm sure there are others. If he wants to piece it you'll need the barrel wrench and blocks to start. The specs for the torque on the barrel nut is pretty broad the hard part is getting the gas tube hole to line up correctly. After that its just a matter of lubing the bolt carrier correctly and you're pretty much good to go. I've got a couple of buddies that have built more than I have so if you have specifice questions I think I can get an answer for you. I also know a gunsmith that was an AF armorer but I only see him about one a month at gun shows. Just make sure the barrel nut is down firmly but don't do a gorillia on it. Good luck. AggieEE

[Dale in Louisiana]

If you buy a ready-made upper, the rest of the exercise is an easy coffee-table job. You'll need simple hand tools like punches and a soft hammer, screwdrivers, and a wrench to tightened the buffer tube. If you have the upper sitting there, you should have the lower put together in half an hour.

dale in Louisiana

[cricco]

If you have a complete lower, then a complete upper takes seconds to put on, with no tools. Just 2 takedown pins.

[SteveUSP]

You also need to think about the caliber you want. 223/5.56 is by far the most common, but there are several other options, like 6.8SPC and 300 AAC for example.

[wch]

If you decide to put it together yourself, watch the videos from Brownells (you tube) on how to build your AR-15.
After you get the parts together (which is the hardest part of the job; be sure to ask all of the suppliers about compatibility with other manufacturers parts and ask all of them that you deal with about return policies before you buy!)
A good book (I used one of Zediker's) is a real help, but when you get into the build you'll find that there's actually very little "gunsmithing" involved...it's more like putting together a kit.
If you decide on a precision match-grade weapon, then things are very different and that's when you get the pro's involved and/or buy prebuilt modules which are guaranteed to do what you want.
I've built 5 uppers (5.56 NATO with a Wylde chamber, 223 Remington, 6.5 Grendel, 6mmAR, and 300 AAC Blackout) and four lowers with another on the way.)
I use Timney drop-in triggers if possible, (one lower has a Jewell "match" trigger for NRA competition) and I have standardized on 20 round magazines from Magpul.
Anyway, building your own is fun and instructive; if you try it, let me know if I can help with the "sticky" parts.

[wv109323]

There is no special tools needed for the lower receiver. With common hand tools and punches you should be alright. The critical things for the upper receiver are torquing the barrel to the upper receiver. A special spanner wrench is needed to fit the "nut" that holds the barrel on. Many of the spanner wrenches has a 1/2" square to insert a torque wrench. The other thing is holding the upper receiver stationary while the barrel nut is being torqued to the upper. The upper is hollow and fairly thin aluminum. A vice block that is custom made for the upper is almost a necessity to keep from damaging the upper. The second and most critical thing is the head spacing. The rotary bolt fits into the barrel extension. You need some way to verify the head space is correct when the bolt is in the "battery" position. Of course the obvious thing to use are the "go" and "no-go" gauge for the caliber being used.
If you can handle the above and have some gunsmithing experience you should be O.K.
As others have mentioned you can buy an assembled,headspaced upper that goes right on. Again the market is crazy right now.

[destrux]

Be real careful driving the roll pin in that holds the trigger guard. The ears on the receiver will snap off easily if you don't support it well.

Also, be aware you can install the hammer spring backwards, and the result will be that the trigger pin will work it's way out since the hammer spring hold the pin in place.

Really... you should buy a book. I got Gunsmithing the AR-15 by Patrick Sweeney and it was very helpful in choosing parts and assembling them... and troubleshooting after my trigger pin fell out (haha). I also used the Wheeler Engineering combo wrench, which was plenty tough enough for the job.

[tomme boy]

Everyone has covered most everything you will need to know. Except! Which barrels fit which upper receivers.

Here is a pic that shows what i'm talking about.

http://img.photobucket.com/albums/v21/tommeboy/feedramps2_zps0a7e62d0.jpg (http://smg.photobucket.com/user/tommeboy/media/feedramps2_zps0a7e62d0.jpg.html)

Also, NEVER buy a barrel if the extension is not already installed. The extension is what sets the headspace. It is pinned in place and will need to have the HS reamed to make it work with a new bolt. As most chambers are chrome plated or nitrated, good luck.

You don't really need a HS no go gauge as the hs SHOULD be set already when you get a barrel.

[tomme boy]

Oh ya. When you torque the barrel onto the rec., do it at least three times. Tighten it up, then loosen it. On your final time, Then line up the hole. The spec for torque is like 25-80 ft/lb. What I do it torque it to about 30-40 and see where the hole it is. If it looks like I can get to the next hole, I go for it. Make sure to lube the threads with moly grease to get a good reading. I like to be on the higher end of the torque setting. But do what you like.

[runfiverun]

if it's a complete lower.
you just need an upper with the correct pins.
then it is a matter of a bolt and such depending on the caliber you pick. [which should come with the upper]
if it's all there, it takes about 15 seconds to put it together.

if it needs a parts kit installed then the above advice is correct.

[montana_charlie]

Anyone who's built on of these things, what do I need to know and what advice or recommendations would you have?
I've built more than one, and will probably build more in the future. But, I don't go for the bells and whistles.
There's nothing wrong with them, but my requirement is a long-term capable rifle that will last till I die.

You should (or your son-in-law should) first decide what style will be wanted ... rifle, or carbine.
If carbine, how short?

Then, pick a barrel and twist rate. A 1 turn in 7 inches is the military twist chosen to stabilize the 'new' SS109 bullet.
But, 1 turn in 9 inches works perfectly well, and is very comfortable with the old 55 grain bullet.
Chrome lined is the military way, but plain chromemoly steel is what our normal guns are made of ... and, there is stainless steel.

Now, for the rifle or carbine, decide on sights ... irons, a scope, or some other optical sight?

I have built very generic 20-inch barreled rifles with standard (A2) front sights, and flattop receivers to take 'whatever' sights.
They basically resemble the standard issue weapon for a Marine.

Once you (or he) has all of the 'features' chosen, the building is just a matter of downloading about six videos that step you through each section.

CM

[redneckdan]

The key to AR specific accuracy is to float a good barrel...thats it. As long as nothing binds up it doesn't matter how the upper fits to the lower. It can be all rattly loose and makes no difference at all. Might bug the operator but the rifle don't care. The lock up is all controlled by the bolt/ barrel extension interface. That is set by the manufacturer of the barrel. Nothing to bed, nothing to blue print, everything else is enhancement of the platform with respect to the operator; ie triggers, sights, stocks, etc...

Look at White Oak Armament for barrels. These things are like Legos for adults. If you have enough attention to detail to fly a damn airplane you can more than handle building an AR.

[MtGun44]

See if you can buy a complete CMMG upper in the config you want. Saves
a bunch of work and their stuff is absolutely first rate. Worth waiting if you
have to.
This is the Barbie doll of guns, a zillion different "outfits". Try one and see
what you like. IMO, a lightwt gun is preferable to a HBar for most real
world applications.

Bill

[seagiant]

Hi,
I was lucky and built my Ar-15 right before the Sandy Hook incident! Parts were hard to find then but doable. I used a DD barrel and bolt. I try to get the barrel and bolt from the same company. I would gather parts as I could find them and put it together myself!

[garym1a2]

As posted above, put your money in a good barrel and a good bolt.

[dkf]

Sounds to me like you are best off buying a complete upper. It will go right on the complete lower and be ready to go.

Don't know what your budget is but a you can't go wrong with a complete upper from Bravo Company. That is route I went on mine and they are top notch quality pieces. http://www.bravocompanyusa.com/AR15-Upper-Receiver-Groups-s/1.htm

[km101]

Best advice I ever got on building an AR was to call these guys up in Whitewright, TX. They have all the parts, tools and know how to get the job done right. If you really want to cut to the chase, buy a complete upper from them and DONE!

http://www.model1sales.com/

They are knowledgeable and helpful, and they are only a short road-trip away if you want to do some "hands on" or look before you buy.

[tomme boy]

Stay away from Model1sales. A few years back they had someone that was stealing the CC #'s from them and they knew it for over a year and would NOT do anything to fix it. I and about a few thousand others on AR15.com got hit. I caught mine and cancelled the card before they got too far.

[BD]

This really depends on your goals for the rifle. A basic 16" barreled AR in 5.56 or .223 is a pretty straight forward assembly job. Good quality compatible parts will give you a good quality rifle. If your goal is a little higher; something that will shoot 1/2 moa or less, a better barrel with matched bolt and a couple of additional steps will help get you there. Still not rocket science.
BD

[Screwbolts]

After you build your first Armalite Rifle, it will be very hard to stop, they are fun. I am working with 80% billet lowers right now. BCG are available right now from AIM Surplus.

Laus Deo,

Ken

[Blacksmith]

Here is a thread from Maryland Shooters Forum that has some good information for people thinking about a build, particularly in post #1.

http://www.mdshooters.com/showthread.php?t=23086

[sparky45]

If you're going to built the upper yourself, you will need the specialized tools such as the upper vise block set, a torque wrench, a barrel wrench just to name a few. Unless you plan to build more than one, and I must warn you, it is addictive then you can figure that cost against simply buying a complete upper. I went the other way, I built the lower and bought a complete upper(300AAC).

[BSalty]

Pretty much everything has been covered here, however one thing, a person stated you don't need a go/no-go gauge. Since this is your first build I highly recommend using the gauges. If you think it looks locked up by eye and it's not, or if something was machined wrong and you have that long and loose chamber, you will have a very bad day. JMHO but I still use the gauges every time.

One thing I have picked up over multiple builds from a pile of parts is some of the free floated hand guards take proprietary wrenches. YHM and Troy come to mind. Just use a strap wrench (be careful not to crush it though) and I have never had one that I could not get on using it. The Troy is a serious PITA to get right, but it is an excellent product. I refer to ARs as the Jeeps of the gun world. You can just buy anything premade and bolt it on and it works.

Good luck.

[Recluse]

Much thanks and appreciation for the replies, advice and PM offers to help out on this project.

I'm guessing that when Ricky adds up and sees the cost of finishing this thing out, there will be a lower up for sale. He's certainly not crazy about AR-15s and I have zero use for the things having had my fill of them in the service and in law enforcement. I'm thinking that the initial enthusiasm for the project may be waning, but we haven't talked about it since I posted the original message.

:coffee:

[smokey496]

He want have any problem selling it. I'd buy it if the price was right.