AR15 Build

I was randomly browsing through reddit one day and came across a DIY build for an AR15. The guy had built a really nice AR15 from the ground up. I've always owned guns, but honestly never had much desire to buy an AR15. To me, they always seemed overhyped and I just assumed people were just buying them to spite Obama. Little did I know, however, they are beautifully engineered and their modularity, reliability, and reasonable price make them one of the best rifles on the market. I still have no desire to buy a stock AR, but the idea of creating my own from parts is really appealing. I'll use this page to document the build over the next few months as I slowly start acquiring parts and putting it together.

Research

Components

• Lower Receiver - The bottom assembly that houses the trigger, safety mechanism, buffer tube, and magazine. This is the only part of the gun that requires an FFL to purchase (unless an incomplete 80%). These come in 3 flavors:
  1. Stripped - An registered, incomplete lower that requires assembly before using and an FFL transfer to purchase
  2. Complete - Assembled lower with buffer, trigger, safety, pivot pins, etc.
  3. 80% - a mostly finished receiver that requires some drilling/milling in order to open up a cavity for the trigger/safety mechanism. Does not require FFL transfer to purchase.
• Upper Reciever - connects to the lower receiver via the pivot pins and attaches to the barrel and handrail.
  1. Stripped - requires a minimal amount of assembly to attach the ejection port cover and optionally a forward assist
  2. Complete - generally include ejection port cover, forward assist, and sometimes one or more of the barrel, gas tube, rail, BCG, and charging handle
• Bolt Carrier Group (BCG) - an assembly that includes the bolt, extractor, and firing pin. This rides inside the upper and is manipulated by the charging handle. These come in a variety of competing finishes including Nickel Boron, Chrome, etc.
• Charging Handle - Long handle that slides into the back of the upper receiver and pulls the bolt forward and backwards in order to chamber a round.
• Barrel - Come in a variety of shapes and lengths. Anything shorter than 16" requires a Small Barrel Rifle tax stamp ($200). 16" is a very common length and is considered a carbine. There's also commonly 18" and 20" barrels that generally increase velocity and accuracy.
• Flash Hider - connects to the end of the barrel and redirects gases when firing. Depending on the style, these can minimally reduce sound and some recoil
• Handrail - generally runs along the barrel and provides places for various components (flashlights, sights, etc.). There's various styles and standards of handrails tailored to specific brands of components.
• Furniture - generally includes the grip, stock, magazine, and various other non-essential attachments. These attachments often come in a variety of styles and colors.
• Forward Assist - Some upper assembly's have a button in the back that can be pressed forward to ease the bolt forward and seat a round. It's debatable whether this is actually useful and they are rarely, if ever, used. Many people recommend them regardless though since the extra cost is minimal and there are no downsides to including it (other than aesthetics).
• Optics - scopes and/or red dots sights mounted on the upper or handrail. Scopes and red dots can be used in conjunction for targeting longer range.

Terms

• Minute of Angle (MOA) - used to mean different things, but this typically refers to 1 inch of accuracy at 100 yards. 1 MOA means 1" at 100 yards, 2" at 200 yards, 3" at 300 yards, and so on. 2 MOA means 2" at 100 yards, 4" at 200 yards, etc. For red dot sights, the term is often used to describe how precise the dot will be at various distances. A 4 MOA red dot sight will cover a significant 4" of the target at 100 yards, 8" at 200 yards, etc.
• Small Barrel Rifle (SBR) - Any rifle with a barrel shorter than 16". Apparently a shorter barrel (14.5") can be used, but the flash supressor must be semi-permanently affixed to the barrel in order for this to be legal. There's apparently some subjectivity and interpretation in these laws and some people play in the grey area.

Builds

In this section, I'll document some builds that I like and start putting together my wish list for parts.

PixeltatedNinja - Budget

link

Anderson Lower - $60 - LGS
BCM Blem Upper - $80 - bravocompanyusa.com
PSA MOE Lower Build Kit - $130 - palmettostatearmory.com
PSA Blem BCG - $75 - palmettostatearmory.com
Schuyler Arms 16" Melonite 1:7 twist barrel - $100 - schuylerarmsco.com
Rouche Sports 15" Handguard - $70 - rouschsports.com
JBO Adjustable Gas Block - $30 - joeboboutfitters.com
Seekins Gas Tube - $16 - joeboboutfitters.com
JBO Charging Handle - $18 - joeboboutfitters.com
A2 Flash Hider - $7 - joeboboutfitters.com
Crush Washer - $3 - joeboboutfitters.com
PMag 30rd - $12 - Cabela's
Bushnell TRS-25 Reddot w/riser - $99 - Amazon
(Splurge) Magpul B.A.D. - $20 - Cabela's

Fenucker

link

Rainier upper receiver 50 
Rainier lower receiver 130 
Strike industries dust cover 13 
Battle link minimalist stock 50 
Rainier Avalanche charging handle 75 
Geissele M-Lok handguard 13in. 240 
Geissele gas block free 0 
APF Armory Bolt Carrier Group 120 
Buffer tube 35 
Surefire Procomp muzzle brake 50 
PSA lower parts kit w/pistol grip 80 
MAS defense .223 Wylde barrel 150 
Carbine gas tube 15
Total is 1010

Accessories
Strike industries forward curved grip 40
Samson micro red dot mount 55
Primary arms micro dot 170
Magpul bad lever 25
Magpul iron sights 75

wwojlo - SBR

link

AlexandRyanDesign - SBR

AR (10.5 SBR):
Odin 10.5" 223 Wylde Barrel
Odin XMR Battle arms Development BAD ambi safety selector
AAC Mini Comp Muzzle Device
AAC 762 SDN6 Suppressor
Lantac-USA EBCG
V7 Weapon Systems Titanium Gas Block
V7 Weapon Systems Titanium Forward Assist
V7 Weapon Systems Titanium Takedown Pins
V7 Weapon Systems Alloy Upper Receiver 
CMC 3.5 Flatbow
MAG Tact Magnesium Alloy Lower
YHM flip up sights
YHM Coated Gas tube
BCM Mod4 Charging Handle
Fortis REV 9" Rail
Magpul Grip

Lightborne - 16"

Aero Precision M4E1 complete 16" upper .223 wylde w/ 15" m-lok handguard
Anderson lower
Anderson LPK
Anderson carbine buffer
Seekins billet trigger guard
Seekins billet mag release
BCM Gunfighter mod 1 grip
Magpul UBR stock
Hiperfire 24c trigger
FailZero EXO NiB BCG
AXTS Raptor charging handle
Magpul MBUS Pro sights
VG6 Epsilon muzzle brake

Kaky - Budget

Very basic budget AR - probably wouldn't want to go much cheaper

The cost was around $560 sans magazines and sights. here is the shopping list:
PSA 16" Mid-length 5.56 NATO 1/7 11" SQR Free Float Upper - No BCG or CH - 7780257 ($270)
PSA 5.56 Premium HPT/MPI Full Auto Bolt Carrier Group - No Logo - 39339 ($80)
Palmetto State Amory Charging Handle with Tactical Release Latch ($30)
PSA AR-15 Complete Lower - Magpul CTR Edition - Black, No Magazine - 49177($170)
I bought some Gen2 Magpul mags from my local Cabellas for around $11 each, and found gen1 Magpul flip up sights on ebay for $20 new. so total it was under $600

SeaLegs - SBR

Upper
Ballistic Advantage 12.5” government profile barrel, Modern Series
Ballistic Advantage BCG, phosphate
Aero Precision upper
BCM KMR-10 handguard
A2 flash hider
Lower
Geissele SSA-E trigger
KAK lower parts kit
KAK Shockwave Blade and tube, standard carbine buffer
Spike’s lower
Accessories
MBUS front sight
KAC 600m rear sight
Holosun red dot, solar powered
Magpul BAD lever
BCM keymod panels, BCM QD sling point, BCM QD rear plate

Whiskey Fire - 16"

• Reddit Build

Aero Precision 5.56 Rifle = 519.05
UTG Mid Profile Riser = 8.77
Bushnell TRS-25 RDS = 68.19
Strike Industries Dust Cover = 15.95
MFT BMS Minimalist Mils Spec Buttstock = 44.75
Magpul MBUS = 69.95
Fortis Rev II 14” M-Lok Rail = 228.39
Lancer L5 30 Rd Mag = 16.99
Paracord = 4.99
BCM Gunfighter Mod 2 = 29.95 (not installed yet)

Stratofisher - 16"

Aside from the trigger, a relatively inexpensive build. Trigger is apparently very good, but $200.

• link

PSA Upper and Lower
PSA full auto BCG
PSA Ultralightweight Keymod Handguard
PSA CHF 16" 1:7 Ultralightweight Barrel
Geissele SSA-E Trigger
Mission First Tactical Minimalist Stock
Magpul K2 Grip
Magpul MBUS Sights

Qaest - 16"

Upper: Palmetto
Lower: Palmetto
Charging handle: BCM gunfighter mod 3
BCG: Palmetto Premium 9310
Barrel: 16" 1:7 twist Palmetto Premium carbine gas (made by FN)
Flash hider: YHM phantom
Rail: YHM SLK 12 keymod
Sights: Magpul BUIS
Optic: Vortex Strikefire gen 1
Optic mount: Aero Precision 30mm
Scope covers: Butler Creek
Stock: Magpul CTR
Grip: Magpul MOE+
Magazine: Magpul 20rd gen 2
Trigger: Geissele SSA-E

Construction Guides

• Detailed AT15 Step By Step Assembly - Really nice step-by-step guide that explains construction and testing of an AR
• Barrel Length - 16, 18, or 20" - 18" sounds like a good all around pick
• M-Lok vs Keymod - general consensus seems to be that M-Lok is better supported, but keymod is more functional (vhs/beta)

Suppliers

General

• Palmetto State Armory - these guys seem to be a very popular supplier with a decent price/quality ratio

Lowers

• Lockestone - Beautiful, but very expensive 80% Lowers. They also sell a reasonably priced, reusable jig that is supposed to work with any milspec lower
• Tactical Machining - Inexpensive and popular 80% lowers

BCG

• Primary Arms BCG - recommended, relatively inexpensive BCG ($159)
• BCM BCG - Another inexpensive BCG ($169)
• Daniel Defense Chrome BCG ($150)

Charging Handles

• Raptor Charging Handle - popular charging handle ($60-$80)

Rails

• Giessele 15" Rail - Nice rail system. ($275)

Trigger

• Larue Trigger Kit - this kit comes highly recommended and is a cheaper alternative to the Gieselle SSA-E ($124)

Optics

• Hybrid Sight III - Recommended by a friend. Not cheap, but maybe some day..
• Primary Arms Red Dot Optics - Until then, this is a highly recommended alternative for under $100
• Bushnell TRS 25 - Another highly recommended, low cost red dot optic.
• Aimpoint Pro - Somewhere between the eotech above and the inexpensive TRS-25

Furniture

• Magpul - These guys have a full line of attractive, modern furniture that are very popular
• Daniel Defense - Attractive Pistol Grips

Ammo

• Gunbot - Bot that scrapes current prices for ammo and allows easy sorting by price per round.

Parts List

The goal was to keep my costs below $1000. I probably could have gone cheaper with a few things, but I think I should easily be able to meet my goal and will end up with a much nicer rifle than I would have gotten by buying pre-built.

Patriot Defense Arms stripped lower - $110 (2/12)

I picked up my first two parts tonight. A friend from work knew someone that was trying to get rid of a bunch of stuff and happened to have a Patriot Defense Arms Stripped Lower. The company appears to be out of business, but it looks like a well-made, mil-spec lower. I had originally planned on starting with an 80% lower, but I think this will actually work out better. I think my dad and I can use this one to mil out an 80% without the $80 jig. If all goes well, this will get me two lowers (one stripped, one 80%) for around what an 80% and a jig would have cost. And if it doesn't work out, I'm only out the $40.

Unfortunately at $110, I think I paid a little more than it was worth (especially considering the company is now defunct), but it was a friend of a friend and he was really helpful. He spent a good hour going through everything he's learned about AR's (and gunsmithing/shooting). I can easily make up the $10 or $20 premium I probably paid.

Lower Parts Kit - $50 (2/12)

The second thing I ordered was a basic lower parts kit. I got it from Schuyler Arms for around $50. At the recommendation of the FoF above, I'm going to replace the trigger spring with a JP trigger spring. Given that they are on backorder, I wish I had thought about getting him to throw one in with the lower, but oh well. I'm sure I can find one somewhere and it's only $10.

JP Enterprises Enhanced Spring Kit - $16 (2/13)

Found on ebay for $16 and free shipping.

Toms Tactical AR-15 Mil-Spec Buffer Tube Assembly Kit - $36 (2/14)

Ordered a standard carbine buffer tube for $36 and free shipping.

Aero Precision Stripped Upper from Monmouth Reloading - $70 (2/23)

I really like the Aero Uppers/Lowers. This seems like a pretty decent price.

Rousch ULS1 V2 M2 Keymod Free Float Handguard - $69.24 (2/23)

From everything I've read, these seem to be really nice handguards. I was leaning towards an M-Lok, but I don't really expect to be mounting much on the rail anyway, so for the price, I don't think I can do much better.

Magpul PMAG® 30 AR/M4 GEN M2 MOE® * 2 - $26 (2/25)

Not much to say about these. They're light, strong, and relatively cheap. Been waiting for them to be in stock for a while.

Magpul CTR® MilSpec Carbine Stock - $59 (2/25)

Not much to say about this. Magpul seems to be the best furniture out there. I toyed with going OD Green, but wasn't sure how it would turn out and was having trouble finding inventory. Finally settled on black.

AR-15 X2 Scorpion Recoil Pistol Grip - $20 (2/26)

Hadn't really planned on replacing the standard grip so soon, but I really like the look of this one and the grey will hopefully break up the black a little bit.

Strike Ind. Ultimate Enhanced (U D C) Cover - $15 (2/28)

The observant among you will notice that I already bought one of these. Turns out I bought a cover for an AR10 and it's too wide for the AR15 upper. This one is actually plastic and has some patterning on it. Not sure how I'll like it, but if it doesn't work out, it was relatively cheap.

BCM Mod 3 Charging Handle 5. 5 6 / .2 2 3 - $50 (2/28)

Was originally planning on doing the Raptor charging handle, but decided to go with a BCM instead. Most people seem pretty happy with them, it's a little cheaper, I don't care about ambidextrous, and I liked the look.

Rock River Arms Chromed Bolt Carrier Group - $130 (3/4)

Really wanted a chromed BCG for completely irrational reasons (I like the way it contrasts against the black upper). There's probably more practical and less expensive picks, but RRA seems to have a good reputation.

AR15Performance 16" 5.56 STD Scout barrel, Wylde chamber 1/2-28 - $150 (3/20)

I finally broke down and bought the barrel. I wanted to get the barrel right, but there are a LOT of options and a lot of variance in price. I've also noticed that the barrels aren't generally discounted like many of the other parts I've been shopping for. I went with an AR Performance barrel. Even once I decided on a manufacturer, the vast selection of barrels was pretty daunting so I hit up the company. I asked:

Hi. I'm sure you get a million of these, so I apologize in advance. I'm looking for a barrel for a 16" 5.56 AR15 I'm building (my first). Your barrels come highly recommended, but as a newbie to all this, I'm a little overwhelmed by the selection. My price range is $100-200 shipped and I intend to use it between 50-300 yards. I'd like to have something that has a good mix of accuracy, low weight, and flexibility with a wide range of (primarily inexpensive) ammunition. I'd prefer steel w/ a black finish. Could you make a recommendation?

And the next day got back:

The Scout profile barrels are lighter than the rest. Both the STD(standard grade) and the 5R barrels have Wylde chambers so both will be accurate with decent ammo but surplus (fmj)ammo is not decent or accurate. They say “crap in, crap out”. For a blaster, truck gun, home defense or even 3 gun either of those barrels would work fine. If you want to sit at a bench and try to shoot smaller groups on paper then the 5R barrel would be more accurate. Black Hills 69gr remanufactured ammo can be very accurate (1/2”@ 100yds) out of those barrels when a good scope, good trigger, good rest and proper shooting techniques are used. Hope that helps

I'm really not interested in bench or match shooting. 3 Gun sounds kind of fun, but I don't plan on being doing it competitively. Given all that, I went with the lighter-weight 5.56 STD Scout barrel for around $150. They seem like good people. I'm not crazy about some of the anti-Islamic rhetoric on their site, but that doesn't seem to be particularly uncommon in this hobby.

Update: I ordered this late Sunday night. It was delivered on Tuesday afternoon via FedEx. We're both in Tennessee, but it's still impressive. Many of the gun parts I've ordered haven't shipped for several days.

Yankee Hill Low Profile Gas Block & Gas Tube - $45 (3/20)

From what I've read, these tend to go on tight, but they have good reviews, are cheap, and worst case, I may just need to sand a little bit off. I ordered 3 extra gas tube pins just to be safe.

Still needed - $100-200

• Raptor Charging Handle ($70)
• BCG - I'm having a really hard time finding a good nickel boron coated BCG ($100)
• Barrel/Gas Block/Tube ($200)
• Optics ($100-200)

Build

Constructing Lower

Got my lower parts this morning.

Lower Assembly

I'm still waiting on some oil, grease, and a wrench to finish it out, but it's mostly done. I really enjoyed putting it together and am kinda sad it's done. I can see this being addicting. On to the upper..

Upper Assembly

Furniture

Bolt Carrier Group

Trigger Guard

A friend of mine 3d printed me a trigger guard. After cleaning it up with a little bit of acetone, it came out really nice.

Barrel

Almost done..

Crafting

Painting w/ fingernail polish. And yes, if all the other preppers jumped off a bridge, so would I.

Gas Tube, Port, and Suppressor

Surprisingly, this was the most difficult part of the build. The gas port did end up being way too snug. I used some 220 grit to sand it down a bit. The gas tube roll pin was a beast to get in, and when I did finally get everything back together, I realized that I ordered the wrong size tube. Turns out, just because you have a carbine rifle, doesn't mean you need a carbine gas tube. After realizing my error, I found on AR15 Performance's website that my barrel uses a mid-length gas system. I have another tube and a couple extra roll pin's on order.

This rail was actually kind of a pain to get right, too. After tightening the barrel nut down snug, it ended up being in the wrong position to tighten the handguard down. I tried tightening it more, but it felt way too tight, so I ended up having to back it back off. It came with some spacers, so I think I'll need to try those. The handguard is in a good position now, but I'd prefer to have the barrel nut tighter.

The flash supressor needed to be wrenched down pretty tight too, since it is a timed A2. Unfortunately early in the process I didn't have my upper mounted in the vice very well and I ended up scratching it a little bit. It's really not too noticeable, but it will bug me.

What I ended up doing that worked much better was to put a piece of thin wood between the upper bottom/top and the teeth. This held it very firmly without scratching the metal, but I wish I had just bought a vice block. So minus the gas tube, here's the completed rifle.

Lessons Learned

Here's a few things I would do differently if I was starting over.

1. Don't build an AR at the beginning of the year. A lot of people use their tax money to buy guns and the prices are generally higher.
2. Buy a partial lower parts kit like this one. I was planning on doing my own grip and trigger kit anyway, so there was really no reason to buy a complete kit. I could have saved around $20 this way.
3. Figure out exactly what you need before you start buying. I had planned on moving slower, but got caught up in the excitement of the build. I passed up on lots of good deals because I didn't know I needed them. Similarly, I jumped on some deals that turned out to not really be "deals". This probably cost me $100 over the entire build.
4. Be patient. Multiple times over the course of my build, I've found the items I purchased the night before for significantly less. Unfortunately shopping for AR parts is not as easy as buying computer parts. You may need to spend a few weeks shopping for components in order to figure out what prices are low, and which are marked up at premium.
5. If you build the upper yourself, buy a vice block. They're only $10-15 and you'll need it for the suppressor and barrel nut. I tried to improvise something and ended up scratching my upper.