AR-15 80% lowers

[chodemeister]

Does anyone have any experience buying 80% lowers? I have a some questions:

What is a reputable company to buy them from?
What is the best option: Forged or Billet, 6061 or 7075? Not interested in polymer.
What should I expect to pay?
Do they come with a flared magwell?
Do tolerances matter?
I have seen them described as having a broached magwell. What does this mean?

 

[2in1evtime]

6061 is slightly easier to mill out, but i prefer 7075. You will find different brandsandprices are all over the place!

 

[NoGoJoe]

Most of what I've seen are 7075-T6 Aluminum 80% lowers. Cheapest I've seen (recently) is about $80 + shipping, most in stock aluminum lowers are running about $90-$100 + shipping. Are you buying a 80% jig? I have the gen 3 jig from 80% Arms at it is essential to milling out any 80% lower. No idea about the types of magwells.

 

[rob63]

Broaching is a manufacturing method, kind of hard to describe, but think of it as passing a series of ever larger cutting teeth through an object with the final set of cutters being the final size. Why it would matter what method you use to get to the final size I have no idea, assuming it is within spec.

I have no experience with 80% lowers, but from an engineering viewpoint, I would prefer forged to milled, assuming both are within spec.

Yes, tolerances matter.

 

[NoGoJoe]

rob63,

Thanks for the clarification on broaching. I've done a couple 80% lowers with the 80% Arms jig.... the jig guides you very well as you slowly (and I mean slowly) mill out the FCP 1/16" at a pass with a carbide mill bit on a router. It's a slow process but the results with a good jig and some patients are on point with the Aero lowers I've purchased.

 

[decalguy]

What about the legalities of owning an 80% gun? I've been looking into buying one myself. I'd love the challenge of building one, I enjoy working on guns. The site I checked is out of stock on most parts now. Reputable companies?

 

[Gd999]

Spend the money and get the 5D tactical mill. It’s about $300. And you will need a dewalt router DWP-611. I think you need the toolkit and the endmill type B for that router. The 6061 is easier to mill and doesn’t need a trigger guard. The 7075 is best but is harder to mill. That is obvious when you first mill one. The 7075 needs a trigger guard. The only part you might use up is the end mill going through the 7075 lowers. I had a 3 month wait to get my 5d jig. It makes it a piece of cake but there are a few tricks. Message me if you get one and I’ll be glad to give advice.

here is the jig.

80 Percent Lowers & Uppers, Build Kits, Tools & More | 5D Tactical

5D Tactical is your supplier for premium quality 80 percent lower & upper receivers, 80 pistol frames, parts, accessories & more. Shop our wide selection today!

www.5dtactical.com

I’ve done about 4 of them and plan to do one more. I paid about $100 for the 7075 and roughly $60 or so for a 6061.

 

[NoGoJoe]

5D tactical and 80% Arms both sell what appears to be the same jig, and @Gd999 is absolutely right, you need a good jig to make a legitimate lower.
Matrix Arms sells a very good 7075-T6 Aluminum Forging 80% lower, it'll take a while for them to ship the lower, but they are good. I got a couple and have been very please with these.

 

[NoGoJoe]

What about the legalities of owning an 80% gun? I've been looking into buying one myself. I'd love the challenge of building one, I enjoy working on guns. The site I checked is out of stock on most parts now. Reputable companies?

I am not a Constitutional scholar, nor a lawyer, but everything I've read indicates (in the state of Indiana) you are permitted to make a firearm for personal use without any registration or governmental approval. If you're intent is to make firearms for resale, then you need to register and be licensed. As I put in a separate post, Matrix Arms has a very nice 7075-T6 Aluminum Forged 80% lower. To build it out correctly, you'll need a good jig (80% Arms Gen 3, Modulus Arms, or 5D Tactical), or a friend with one. It is a cool project, but it does take some time to properly mill out a aluminum 80% lower.

 

[chodemeister]

Thanks everybody for the valuable input! I think that forged 7075 with a flared magwell is the best way to go. A little extra money, but I think it is worth it.

 

[NoGoJoe]

One more piece of wisdom; many of the videos & directions say to use WD-40 to lube the mill while milling out the aluminum. Do yourself (and the mill bit on the router) a favor and pickup some Thread Cutting Oil, it'll work much better.