building a complete ar-15 lower reciever

8/8/2019 Building a Complete AR-15 Lower Reciever

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Building a complete lower receiver from a stripped receiver, step by step:

(or..... "assemble your own lower for dummies") This web page will demonstrate just how easy it is to build a lower receiver from a stripped receiver. This whole process, start tofinish, takes 30 minutes to an hour.... depending on your skill level. If you can poke small objects into small holes, then you can build your own receiver.

There is a good reference for this whole procedure posted here:www.ar15.com/content/guides/assembly/lower/however the guide below is a simplified version with realpictures to show you how easy this is to do.... if you are on the fence.

SUPER video of the entire process by DVDTracker here:

www.lifelibertyetc.com/RangeBag/Video/LLE_AR15StrippedLower.wmv

Ok, lets cover the necessary tools. What you need:

Honestly... there are NO special tools necessary. Some will argue its good to have roll pin holder tools, roll pin punches, etc..etc... the only tools I feel are really necessary are a smallbrass punch.... and light hammer. Everything else can be improvised.

Thats it for tools! Now here are the step-by-step instructions:

There is not really a special order you have to go in... common sense will tell you some things have to be put in first, before others... but for the most part its not really important.The order shown here is just the way I happened to go... I started with a stripped lower receiver:

Here is the parts list that comes with a lower parts kit....
http://www.ar15.com/content/guides/assembly/lower/http://www.ar15.com/content/guides/assembly/lower/http://www.ar15.com/content/guides/assembly/lower/http://www.lifelibertyetc.com/RangeBag/Video/LLE_AR15StrippedLower.wmvhttp://www.lifelibertyetc.com/RangeBag/Video/LLE_AR15StrippedLower.wmvhttp://www.ar15.com/content/guides/assembly/lower/


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ClickHEREfor a bigger and detailed parts kit photo.

Here are some helpful pictures on the trigger and lower parts kits, common areas of confusion:
http://www.kevinholman.com/byor/lower/partsbig.jpghttp://www.kevinholman.com/byor/lower/partsbig.jpghttp://www.kevinholman.com/byor/lower/partsbig.jpg


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1. Insert the mag catch on the left side of the receiver (side with all the words on it) and then install the mag catch spring from the right side.

Then, grab the mag catch button and push it towards the mag catch. Then, spin the mag catch to tighten it. Stop when the mag catch threaded post is flush or nearly flush with thebutton:


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2. On to the bolt catch. Get some masking tape and cover the lower receiver here: This is to keep accidental scratching from occurring as we tap in the bolt catch roll pin in place.


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Insert the roll pin, and tap lightly to get it started... but do NOT tap it all the way in yet. Insert the bolt catch spring and buffer, with the spring in first and the buffer facing out:


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Then, install the bolt catch, holding spring tension on the plunger, while aligning the hole in the bolt release with the roll pin hole in the lower.... and using a punch, tap the roll pin allthe way in. If you want to avoid marring the finish, place more tape over the roll pin area as it gets close to flush to drive it all the way home.

3. On to the front pivot pin. Some people have trouble with this one, with the detent being lauched across the room. Just be careful, and its really no big deal. insert the spring intothe detent hole:


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Then insert the detent. It will barely even start in the hole before you really have to push for all the spring pressure. Then, using the pivot pin, push the detent back while you insertthe pivot pin into it's hole in the receiver. Snap... bamn.... it just falls into place. :-)


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4. Trigger guard. This is pretty straightforward... insert in the trigger guard with single hole side in the receiver. Then align the roll pin hole up with the hole in the "ears" of thereceiver. BE VERY CAREFUL HERE.You must support the "ears" on the bottom side if you tap the roll pin in place. If you dont support the bottom ear, you could break it offwhen tapping the pin in place. Also, some roll pins or t rigger guards are out of spec. If it takes what you think is too much force, or starts to deform your roll pin, STOP. Also - seebelow for an alternative method of installing this pin by squeezing the pin in place.


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5. Drop the trigger and trigger spring assembly into the receiver.


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Then push the disconnector on the top of the trigger, with the notch in the disconnector over the coil spring in the top of the trigger. Then using a trigger pin, insert it through thelower receiver... into the trigger, through the disconnector, and back into the other end of the receiver. This takes a lot of wiggling to get it though... but you can do it!

6. Next, grab the hammer/hammer spring assembly, and insert it in the lower. The two long legs of the hammer spring should rest on the top of the trigger ping installed in step 5.There is quite a bit of hammer spring tension... but squeeze the hammer into the receiver so that the hammer pin hole lines up with the holes in the lower receiver, and install thehammer pin. You might have to tap lightly to get the pin through the hammer, but just LIGHTLY. Cock the hammer.


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7. Next, install the safety selector into the left side of the reciever. Install the selector detent, and spring into the detent hole:

Install the pistol grip and grip screw, taking care to ensure the selector spring goes into the hole in the grip.

8. Rear takedown pin: Install the detent and then the spring... and the takedown pin into the rear of the receiver. The stock will hold tension on this spring/detent, when it is installed,next:


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Then thread the tube a little more, so that it holds the pin in place, but does not touch the center part of the pin and bind its movement:


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Now, just insert the carbine/rifle buffer and spring. Cock the hammer back to make this easy. The spring goes in first, with the buffer in next... and push the buffer in past the bufferpin sticking up.


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You are all done! Perform a trigger mechanism safety check, install your upper, and go shooting!

Safety function check is describedHERE and HERE

DO NOT DRY FIRE A LOWER. Dry firing of the assembled weapon is fine. However, if you allow the hammer to drop on a lower that does not have an upper installed, it willpotentially damage the lower receiver. The hammer will strike the bolt catch, which will damage the bolt catch receiver area and pin. If you do it a couple times it will be fine... butcontinued dropping of the hammer will likely result in damagin the bolt catch, receiver, or both.

As an alternative to driving pins in with punches, you can press them in:

Originally Posted By A_Free_Man:Here are pictures, how to press in the roll pins in the lower (works also for the roll pin for the FWD asst on the upper, too):

Hold the roll pin in position with needle nost pliers, a little oil or grease in the hole helps:
http://www.ar15.com/content/guides/assembly/lower/#hammerhttp://www.ar15.com/content/guides/assembly/lower/#hammerhttp://www.ar15.com/content/guides/functionCheck/http://www.ar15.com/content/guides/assembly/lower/#hammerhttp://www.ar15.com/content/guides/functionCheck/


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Use large Vise Grip pliers, jaws taped to protect the receiver from scratches. Adjusting the pliers so that they just barely press the pin in

with the handles all the way together gives maximum mechanical advantage:


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Get the pin started in, and put in the spring, detent, and position the bolt catch:


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Continue pressing in the pin by opening the pliers, turning the knob 1/2 turn at a time, and pressing the pin in little by little:


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Now the pin is almost all the way in, it can be tapped in flush with a few light taps on a punch or an ordinary carpenters nail set:


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Now let's do the trigger guard:

Hook the trigger guard in the front, by the mag well, and swing into position. If you don't have the trigger guard in position when you tryto start the pin, it will break off the tab of your expensive lower:


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Press in as in previous post, turning the knob of the Vise Grip 1/2 turn at a time:


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Almost there:


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Now that you have it this far, finish by tapping in flush using punch or nail set:


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Common Q&A:

Q1. do any of the lower receiver parts need to lubed?

A1. CLP is all you *need* for any part on the AR15/M16 rifle.... and at a minum should wipe down the FCG, safety, and pins, with CLP. That being said, on initial assembly, I like touse a little moly-grease on the sear engagement surfaces on the trigger and hammer, and inside the trigger and hammer pin holes. I place a dab of grease on the new pins, and work

them in and out to lube the inside of the new fire control group. I also add a dab of grease to the safety selector, and takedown/pivot pins.

Q2. do you ever find the trigger and hammer pin move, or are they held in place fairly well? Ive seen some locking pins, are they necessary?

A2. If the FCG is installed correctly.... there will be no movement of the pins. There is a "j" hook installed in the hammer that firmly holds the hammer pin in place..... so that cannotmove. Then, when the hammer is installed, one of the legs of the spring rest in the groove on the t rigger pin, so that one cannot move. I dont see the real use of "anti-walk" pinsunless you are running some sort of custom trigger that does not have these designs in place. Or, if you do not want the pins to rotate in the receiver, you can install oversized pinslike in the RRA triggers, or a KNS pin set which locks them from moving sideway or rotating.


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building a complete ar-15 lower reciever

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