Saturday, December 8, 2012

AR-15 Lower Receiver Build

So to start out I had a stripped lower reciever, a DMPS lower parts kit, a Brownells receiver extension AKA buffer tube and stock, some punches and a little hammer. The Glock tools were tossed into the order as they are a nice thing to have. I hopped onto the build guide and got started. It was helpful to have it open in two tabs so one could stay on the picture with the part diagram instead of scrolling back and forth.

Yes that is a tiny hand with a toy truck in the photo. I was getting set up right about his bedtime.

We will start with the Bad, then move onto the Ugly and close with the Good.

The Bad:

Lets just say I am not mechanically inclined. Tiny little pieces that have to go together in specific ways aren't my thing. Imagine if Homer Simpson and the Keystone Kops tried to build an AR-15 lower receiver.

Things got rolling and were going OK until the #*$%)#* #*%$))#*ing Pivot Pin Detent and Spring. Those suckers went flying off to the abyss of our home. After some looking and harsh words I decided to grab the other parts (there are two of each piece) and just keep going. That #*$)(@#ing spring bent but I had a second one. It would probably still work but the idea of using a knowingly flawed part did not appeal to me. That front pivot pin detent and spring are probably the hardest part of the whole lower build. I kept going on figuring this part could be figured out later. About half the parts need to be taken out then put back in but nothing was particularly difficult and I kept a decent pace.

Once I got to the end of the lower build I had to have that other Detent Pin and Spring. Realizing I had some spare parts lying around I decided to see if these parts were on inventory so things could get finished up. Thankfully I had the parts. Getting the rear detent pin in, the buffer retainer compressed and the stock screwed on was kind of awkward. Anyway it got done.

Doing a functions check the trigger was not rebounding properly/ reliably. I then pulled out another lower to take a look. The trigger spring was not properly in place. To take it out I pretty much had to pull the whole thing apart but since I was a bit ahead on the learning curve it was only a 10 minute thing.

All in all it is done and took about 2.5 hours. During that time I ruined/ lost about $3 in parts. I suspect another build would take an hour and not have any lost/ damaged parts.

The Ugly: The implications of lost or damaged parts are significant in some sort of worst case scenario. Folks who plan to build or fully disassemble weapons would be well advised to have some of those little parts on hand. Had this been a worst case scenario and I didn't have the spare parts my AR-15 would be nonfunctional for the want of $3 in parts which would be like really really bad.

Getting into my spare parts I saw we have a less AR-15 spare parts than I thought. Will address this shortage at some point.

The Good:

I know more about the function of the AR-15 than I did before. While the building wasn't fun I am pleased to have done this. Also I learned a new skill. Getting to the level where I am a competent Armorer (able to restore the gun to factory specs) on all of our core weapons and some common other ones is something I want to do.  Also now I have to go to the range to do a test fire which is a good excuse reason to go shooting.


Anonymous said...

"A man who picks a cat up by the tail learns something which he can discover in no other way." - Mark Twain

Congrats on your build. Welcome to the club.

{Free build tip from the video I recommended previously: "If you get an extra set of trigger group pins, and shorten them all by the thickness of the lower receiver walls (grinder/file/etc.), you have a set that allows you to construct the entire trigger group outside the receiver, drop it into place as a unit, line up the pins/holes and then use full-size pins to drive the dummy build pins out.(Save the dummy pins.) Which alo works in reverse for taking the trigger group out for fixing things.}

Best regards,

Ryan said...

Aesop, Thanks. There is so much stuff out there for free that I had a hard time justifying a DVD.

Suprisingly the trigger and hammer were easy and the little ancillary stuff caused the hassles.

Chris said...

I had pretty much the same experience building mine.

I actually saw that Brownell's had lower parts kits minus trigger group for like $25 on Black Rifle Friday. Something like that would not be a bad thing to have on hand in addition to a spare BCG, charging handle, etc if one is heavily vested in the AR platform.

If the spring and pin are still AWOL you may want to vacuum ASAP before Dog or Walker finds and inserts the metal parts into the mouth. I never found mine after they SPROINGED and just got another $3 of parts...

Ryan said...

Chris, Think I got a "field repair kit" as well as a "spring kit" and a "pin kit" for the last go around.

Probably going to make another parts order in the near future.

Anonymous said...

When I lost the spring on my lower build I used a magnet to find it under the workbench. Magnet has saved me several times finding parts amid the dust bunnies they usually land in. I once spent two hours looking for a ball detent before the magnet idea came to me.

The aftermarket trigger I recently installed ( Geissle) came with short pins for installation.

Building a tool kit for each weapon in your arsenal is as important as stocking ammo IMHO.

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