You've learned all about 80% lowers and frames, and now you're hooked on the idea of building your first gun from scratch. But you first want to answer the two most important questions: What's the most affordable (and easiest-to-machine) 80 percent lower for your particular build?
First, Universal Costs
No matter which receiver blank you build, you'll need some universally required tools for this project:
- Drill press for rifle receivers or,
- Hand drill for handgun frames
- Work-holding vise
- Machining oil
- Mill and/or drill bits (included with jigs)
- Some ear and eye protection.
All told, expect to spend around $150 for an "entry-level" drill press and vise setup if completing an AR-type lower. You can spend about $75 to $100 for a good hand drill and vise if you're completing a handgun frame. Sig frames require a small Dremel with a cut-off wheel, too.
Cheapest AR 80% Lowers
Let's get into the most popular receivers first: AR lowers make up most of the 80% market, especially with new calibers and uppers like the AR-9 and 6.5 Grendel being introduced. You don't need a fancy, custom billet receiver to build a rifle or pistol in these new configurations. You only need a good ole' 5.56/.223 receiver (we'll go over .308 stuff next).
Forged, Blemished 5.56/.223 Lower (AR-15)
This forged, blemished lower's the cheapest mil-spec 80% AR 15 lower available for the AR-15. We say mil-spec because this receiver is forged from 7075-T6 aluminum and treated with a Type III anodized finish, like any service-issued rifle. Blemishes on this receiver are entirely superficial, and typically include small scratches in the finish, or small dents that don't affect the integrity of quality of the receiver. Less expensive options will either not come with "FIRE" and "SAFE" engravings, or they will not come with an anodized finish. Other cheaper options can also be made from polymer instead. If you're the Dooms-day-minded prepper, you can bulk-buy a ten-pack of these receivers.
- 300 BLK
- 6.5 Grendel
Fabrication difficulty for this unit is average. It requires a drill press and conventional jig, and total machining time averages 1 to 2 hours.
JMT Polymer Lower & Jig (AR-15/AR-10)
James Madison Tactical partnered with us to bring their updated polymer AR-15 lower and jig combo kit on board. An AR-10 version is available here, too. It's currently the most affordable and probably the easiest-to-machine 80% lower for the AR-15. It's a very rugged receiver, made from a reinforced polymer and redesigned to be even stronger with this Gen 2 version. The exterior of the mag well matches the design found on every Magpul magazine, which is a nice touch. JMT's made fabricating an AR from this receiver easy, thanks to in-depth instructions paired with a simple jig.
- 300 BLK
- 6.5 Grendel
Fabrication difficulty for this receiver is easy. Its polymer material is much easier to drill and mill than aluminum. If you're using a basic drill press and want the least hassle as a new 80% builder, this is a great choice. Total machining time is about 45 minutes to 1.5 hours.
Dedicated 9mm Lower (AR-9)
With pistol calibers being shoved into the AR (and with manufacturers finding it surprisingly easy to do), gone are the days of only throwing centerfire rifle cartridges downrange. The AR platform has become a staple among pistol carbine builders. The dedicated AR-9 lower is the most affordable way to get your hands on a 9mm AR setup. It's cut from billet (6061-T6) and has a preinstalled ejector and mag release specifically made to work with Glock 9mm magazines. It also uses a regular old AR-15 parts kit, trigger, grip, and buffer tube.
- 9mm Parabellum
- Any 9mm Glock magazines
Fabrication difficulty for this receiver is average. It's cut and drilled exactly like an AR-15 lower, since it uses the same 5.56/.223 lower parts kit. A drill press is required and total machining time is 1 to 2 hours.
Cheapest 80% Frames
It's even easier to build a handgun than an AR-15, so we're covering the most affordable and simplest 80% frames for popular handguns like Glock, 1911, and Sig.
SS80 (Glock-type) 80% Polymer Frame + Builder Tools
The polymer 80% Glock-type frame from Single Stack 80, combined with their builder's jig and tool set (sold separately due to ATF restrictions), provides up the cheapest 80% pistol frame you can find. This combo edges out Polymer80's frames by a margin, making for a small savings. Of course, you need to be in the market for a Glock 43 build. SS80's frame is only compatible with the G43's parts, and whichever Glock models the G43 winds up being compatible with. At around the $150 price point, this combo's about $10 to $50 cheaper than most other polymer 80% pistol frames.
- Glock 43 (9mm single-stack)
Fabrication difficulty for this frame is very easy. Completing this frame requires nothing more than an electric hand drill, a pair of snips or a Dremel for cutting, and some sandpaper. Total machining time is approximately 30 minutes to 1 hour.
P80 PF940C Frame and Jig
For a few extra bucks over the SS80 setup, you can opt for Polymer80's PF940C frame and jig combo. This 80% frame is compatible with a few Gen3 Glocks. It's also available in Flat Dark Earth or black, for those who want a little customization. It's otherwise identical in form and function to SS80's setup and your typical, factory-produced Glock frame.
- Glock 19, G23, G32
- 9mm Parabellum, .40 S&W
Fabrication difficulty for this frame is very easy. It requires the same fabrication steps as the SS80 unit, which dictates using a hand drill, Dremel or snips, and sandpaper or round files for final polishing and fitment of parts.
Stealth Arms 1911 Frame and Jig
Polymer's the wonder material of the 80% world, but the age-old 1911 has also received one Hell of an upgrade with new materials. That is, we're ditching that heavy steel frame for lightweight, tough billet aluminum. That means you get the opportunity to build a custom, from-scratch 1911 with hand tools. This frame-and-jig combo from Stealth Arms comes with everything required to complete the frame, like a polymer unit.
- All retail 1911 parts
- Available in 9mm, .45 ACP
We rate fabrication difficulty for this frame as easy. It requires a bit more care and time to cut the slide rails and barrel seat, only because you're cutting aluminum -- not polymer like a Glock-compatible frame. Nonetheless, cutting is surprisingly easy with the provided jig and cutter. It's all done by hand, and no measuring devices or calculations are required. The jig does it for you. Drilling is accomplished with a hand drill.
What's The Overall Cheap and Easiest 80% Lower?
Of all the options we've covered, affordability and machining difficulty tend to go hand-in-hand. Fabricating a firearm from raw materials sounds complicated, but using the appropriate jig and simply following instructions closely makes for an easy project.
With that said, there must be one "easiest-to-finish" 80% unit, and it's the G43 frame from SS80. Being the most affordable unit, the SS80 frame won't leave a giant hole burned in your wallet if you make a major mistake during machining or assembly and you have to start over. It requires the least amount of tools and knowledge to fabricate, too. You probably have most or all the tools you need to fabricate a Glock-type pistol from this frame. Lastly, this is one of the only polymer 80% frames that can be purchased alone, and whose jig can (and must be) be bought separately. So, you can build more than one SS80 pistol without the extra cost of having each frame bundled with a new jig each time.
Completing Your Frame or Lower
Fabricating your frame or lower is relatively straightforward with the correct jig. If you've been following along but are new to this kind of project and don't know what a jig and all these tools are, start here: What's an 80% Lower Jig? This guide covers the introductions on the tools and bits. Once you've learned up, you can check out the instructions for completing each type of 80% lower and frame discussed in this guide: