My Little AR Build: Lower Parts

I mentioned a while back that I bought an AR lower kinda by accident. I decided to make it a Magpul Fanboi Rifle after input from folks at the gunblogger_conspiracy.

Also, in case you’re wondering, subsonic 300blk out of a 20″ barrel has a 44 foot drop at 400 yards. Not recommended.

I bought the AR lower locally. The lower parts kit I got from Palmetto State Armory because they have one that includes some Magpul stuff. They were out of the lower build kit I wanted, which included a stock and buffer tube and all that goes with that, so I had to go elsewhere for those parts.

Because I’m impatient.

I’ll be building the lower over the next couple of weeks (or months depending on how the kids act) using various guides floating around. I’m starting here, and seeing where it takes me.

I hit up Brownells.com and CTD looking for parts, but as it turns out you can build an entire rifle, minus the lower, from Amazon. And it seems to be slightly cheaper.

I’ll be building the lower first, then figuring out what I want to do about an upper. The bad thing about being a Dave Ramsey guy is that you can’t buy something until you have the money for it*. CURSE YOU DAVE RAMSEY!
So here is what I have so far:


ATI Mil-spec buffer tube kit, which I may or may not have overpaid for.

Magpul STR Mil-Spec in Flat Dark Earth because, you know, OH LOOK A SQUIRREL!


Magpul ASAP Sling Plate for when I operate in operations.

I also took the opportunity to buy some tools that I didn’t already have, but need. If this goes well, I’m afraid I’ll constantly have one or two of these in various states of build.


Lower Receiver Magazine Vise Block because, hey, if you’re building one, you might as well build several.


Wheeler 711016 Nylon/Brass Hammer. Coulda used one of these when I was installing my Apex parts in the M&P9.


I already had an Ar15 Stock Combo Wrench that I picked up a few years ago. I don’t actually remember buying it, but I’ve had it for years.

Again, build time is going to be dependent on me actually getting some time when 1)the baby is asleep, 2)the dog is asleep, 3)I’m not worn out from dealing with both of them and 4)all the other stuff I have to do is done.

As far as the upper….what do you think? Buy, or build?

*See, the rule in my house is that I can spend whatever I want on guns, but mrs wizardpc gets the same amount for jewelry, unless I come up with the money myself via selling old guns or saving up my allowance or from revenue from this site. So it takes a while.

6 comments to My Little AR Build: Lower Parts

  • This is highly relevant to my interests as I just bought a stripped lower as well. Thanks for the suggestions! Although your Amazon link just goes to the main page.

  • Critter

    blue locktite is your friend, yanno.

  • Kristophr

    Buy a 4-40 tap, and 1/4 inch 4-40 allen socket set screw.

    Shorten the rear takedown pin detent spring by a quarter inch, tap the first quarter inch of the hole it goes into, drop in the detent pin, the shortened spring, and screw in the set screw on top of it.

    You will thank yourself the next time you change butt-stocks, and that spring fails to launch into the carpet.

  • I got all my internal lower parts from White Oak. John Holliger knows AR’s and I got the Rock River two-stage trigger – but I don’t see that now and I don’t know what the ALG Combat trigger is all about. I didn’t use a vise, I just hammered it together on my desk. 🙂

  • Todd S

    You could build an upper half (you’d get to buy a torque wrench, if that’s your thing), but there are some really good uppers out there. Besides, it’s like the poster says, M4 SOPMOD: Like Barbies for Men!

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