Have you built an 80% lower?

[coloradokevin]

NOTE: this is not a legal question.

Have any of you built an 80% AR-15 lower into a complete rifle? If so, how'd the finished product turn out? Would you put your quality on par with a store-bought AR-15 receiver?

I'm nearing the end of my first AR-15 build, and the bug has definitely caught me (like most guys, I spend too much of my time tinkering with stuff).

I'm thinking of trying an 80% build in the future, mostly just for the novelty of being able to do it. But, this is new territory for me, and I'm only really interested in putting together a quality firearm.

Are the jigs and instructions for these parts of a decent design, and a high enough quality that you can get a good finished product? Which parts would you recommend for such a build?

I'm probably at least a few months out on doing this (blew the $$$ on the current build), but I figured it would be good to research it now!

 

[giggitygiggity]

No, but it seems like more of a pain and hassle and between the cost of jigs, time, cost of electricity, bits, etc., I'd rather pay an extra $20 for a transfer fee and get a serialized lower and not have to worry about screwing something up while milling it out.

 

[MachIVshooter]

How they turn out is going to depend entirely on the tools you use and the care you take.

Some guys have been able to turn out pretty decent results with jigs and routers, but plenty have butchered them that way. Same goes for drill presses. Yes, it is possible to do them that way, but neither of those tools are meant to mill aluminum. You have no rigidity to speak of, and drill presses are not designed for lateral loads on the quill. And while routers can take the lateral load, they generally spin too fast, and it's a hand-held tool.

You've likely seen many of my build threads, including those that go well beyond 80% lowers. But I have done quite a few 80 percenters, and before ATF 2015-1, I let a number of folks use my mill, just gave them some guidance. On a full size knee mill, 80% lowers are a snap. First timers usually take 1-1/2-2 hours, but it is possible to knock them out in under 30 minutes. They come out looking great:





However, I cannot help you with jig advise, as I've never used one. If you are going to use a drill press, I'd strongly recommend one of these rather than a cross slide vise.

I'm happy to try to answer any other questions you have.

 

[oldandslow]

ck,

As M4S mentioned above it involves a lot of time, expense and skill to properly finish an 80% lower. I have done a number of them, both billet and forged. I use a jig to hold the lower upright in the minimill but do not use the top plates to guide the cutting. I use the jig for drilling out the holes in the sides of the receiver. While it has been done with drill presses and routers the results seem pretty ragged.

Then there is the refinishing issue. I invested in a home anodizing setup and do my own anodizing. To do a proper anodizing job also requires time and expense and a good bit of space to put all the different solutions (I have 8 different buckets set up with different toxic solutions (cleaners, acid, lye) at temperatures varying from room temp to 200 degress F). I use www.caswellplating.com as my source for anodizing components.

Then there is the engraving issue. If you opt to have yours engraved in a way that is acceptable to the ATF you need to have something done called "deep engraving" to specific depths and letter heights. It's easier to have it done before finishing the 80% lower as an FFL is not required of the engraver. If you want engraving done after completing the receiver the engraver needs an FFL and the cost goes up (about $30 for a non-FFL engraver vs. $60 for an FFL engraver without shipping costs).

With the costs of finished AR lowers running below $80 it is much cheaper and easier to just buy a completed one and do the transfer at your FFL compared to buying the tooling for an 80% one and having it refinished and engraved. Good luck.

best wishes- oldandslow

 

[Jackal]

Unless you have access to a mill, its very unlikely you will turn out with a finished product on par with a cheap $50 lower. When not using a mill, 80% lowers are pretty much a strictly "because I can" project, since it makes zero logistical sense due to the cost and quality of the finished product. You get to pay more and put time into a product that will likely turn out to be of a lower quality when finished than a factory stripped lower.

 

[Robert]

I have done two 80% lowers now, one on a mill and one with a drill press and router. The one done on the mill looms just as good as anything in a gun store. The one done with the press and router is perfectly serviceable. Though it does not look as nice inside. But honestly once it is coated who cares. Who looks at the trigger pocket anyway?

It is not a hard task but it does take time to do it correctly. I use a bench mounted drill press and a 80% Arms jig to drill the trigger pocket out and then switch to a hand router to mill the material out. It take me about 3-4 hours from start to finish. On a mill that's maybe 30 mins... The big thing is go slow with the router, let the end mill do the work, don't force it.

I am impressed with the 80% Arms jig and lowers. Makes things almost idiot proof.

 

[ColonelKorn]

I would trust my work on the 80%-ers against any 100%-er.

 

[coloradokevin]

Thanks so much for all of the firsthand experiences with this stuff, guys. I must be honest, I've never run a mill before. I used to do some woodworking, so routers and drill presses are familiar territory.

I fully understand that there isn't really any cost savings to making my own receiver (after all, I saw some finished ones on Brownell's today for $44 — add a bit more for transfer fees, but still pretty cheap). Still, I feel like there must be some feeling of accomplishment that comes along with building your own gun from the ground up (well, more so than most people do, anyway).

 

[Robert]

I really like doing the work. A decent mini mill is over $1K and a proper floor mount mill is even more. Sure it is cheaper to buy finished lowers, but where's the fun in that?

 

[MachIVshooter]

A decent mini mill is over $1K

Well, you can get the little Harbor Freight mini for under $500 if you have a 20% or 25% coupon. But by the time you get a halfway decent vise (at least $160 with shipping), DROs (~$120 for 3 axis with IGaging), Collets ($60), a dial indicator ($30), parallels ($40), angle blocks ($40), yeah..........you'll be pushing $1k.

For the record, Seig makes the HF, the grizzly, the LMS. There are some variations between certain models, but they're basically all the X2

 

[coloradokevin]

Well, you can get the little Harbor Freight mini for under $500 if you have a 20% or 25% coupon. But by the time you get a halfway decent vise (at least $160 with shipping), DROs (~$120 for 3 axis with IGaging), Collets ($60), a dial indicator ($30), parallels ($40), angle blocks ($40), yeah..........you'll be pushing $1k.

For the record, Seig makes the HF, the grizzly, the LMS. There are some variations between certain models, but they're basically all the X2

Hmmm. My better half is pretty darn supportive of my shooting habit (I have to be supportive of her equestrian habit in return), but this one could be a hard sell:

"Honey, I need a $1000 mill so I can finish a partially built lower receiver that costs only $60. Of course, I could buy a finished receiver for $60, but this one will be of our very own creation!"

She might let me go for it, but that one could be a tough justification. Lol.

So, maybe you guys will have to give me a comprehensive list of other cool projects I could complete with such a mill, just so I have more ammo for my future discussion. Sigh. Why is fun stuff always so darn expensive???

 

[USAF_Vet]

I don't have a mill, so the 80% route is not an option for me. That's why I'm going with the flat puzzle piece kit and welding up a lower. Would that be a 40%?

 

[Robert]

Again, you don't need a mill, but it sure is nice.

 

[kanook]

Once you spend the money on a mill, you will wonder how you lived without one. I am going to get another shortly because of loss of access to my first one

 

[MachIVshooter]

So, maybe you guys will have to give me a comprehensive list of other cool projects I could complete with such a mill, just so I have more ammo for my future discussion. Sigh. Why is fun stuff always so darn expensive???

Oh, you won't believe the number of uses you find for it, especially in this day and age of having to replace entire assemblies rather than individual parts.

Maybe she breaks her favorite bit, which is either really expensive or no longer in production. Now you can machine a repair piece! Drawer guide in the refrigerator breaks off? No problem!

Heck, I even made my wife a piece of jewelery. Yeah, it was aluminum, but not like anything available, since it consisted of a pendant hanging from a .300" wide chain in which the links are solid (no bending, no welding; think wooden chain, but much smaller).

My daughter broke off and lost the leg of her favorite doll. I made it bipedal for her again:

 

[ironworkerwill]

My daughter broke off and lost the leg of her favorite doll. I made it bipedal for her again:

I don't know why that is so funny to me, good laugh.

 

[ColonelKorn]

I'm going to mill a lower from bar stock some day just to prove I can.

 

[MachIVshooter]

I'm going to mill a lower from bar stock some day just to prove I can.

Go for it! It's fun. Time consuming, but fun. I did my last one out of carbon steel, took about 26 hours.

 

[Brass2grass]

I just finished my first 80% lower. The cost difference of a complete lower vs an 80% lower is about $100 here in CA. With an 80% you also have to buy the jig mine was $84, drill press or mini mill $60-3000, drill bit set $30, end mill set $80-300. If you plan on only building one rifle then I'd just go with a complete lower since you'll save money. My jig was from Daytona tactical and the instructions weren't very good. I bought my press from harbor freight for $69 and the table support broke right away, you get what you pay for. Since I didn't have a traversing vice, there was a lot of chatter going on and my receiver came out looking pretty rough. It was a hassle but I enjoyed it and plan on doing more, just with a better press or maybe an actual mini mill. Being in CA it was worth it for me. Dedicated pistol receivers here are retarded expensive not to mention you have to have a stamp for an SBR. This way i bypass all that crap