Finishing an 80% lower

It really doesn't take much of a mill to finish out an 80% lower - made my own side plates to hold the lower and finished out by counting turns on the wheels.

This was all done on a MicroMill - check out the picture for to see how small it is compared to a lower

Nice work but I think your missing a few holes?

What is the depth of your trigger pocket?
Hard to tell from the photo.
Spec is 1.249
 
Nice work but I think your missing a few holes?

What is the depth of your trigger pocket?
Hard to tell from the photo.
Spec is 1.249

I'd have to take it apart in order to get a measurement but, other than some internal cosmetic errors from missing a layout line, it works great.

If I were to finish another lower in this mill, I would drill out the majority of material instead of milling everything to make it easier.
 
So if I have say a Polish parts kit with a fixed stock it really doesnt matter what receiver I get, as long as its for a fixed stock and the caliber matches. Is that right?
Correct. There are some exceptions though. Yugo kits have a bulged trunnion and Chinese have thicker sheet metal 1.5 mm vs 1 mm standard. Childers actually uses Polish blanks to start with. You can get them with Polish markings. He scrubs them to put other countries markings on them. Recreator uses US flats then finishes them to their appropriate country. Check out AK Files for all your AK building questions.
 
Correct. There are some exceptions though. Yugo kits have a bulged trunnion and Chinese have thicker sheet metal 1.5 mm vs 1 mm standard. Childers actually uses Polish blanks to start with. You can get them with Polish markings. He scrubs them to put other countries markings on them. Recreator uses US flats then finishes them to their appropriate country. Check out AK Files for all your AK building questions.
Thank you
 
If you tell me that you turn handles and watch dials to finish out a 0% then I would be impressed...[troll][troll][troll][troll]

If you count turning a jog wheel to probe the raw stock than sure... otherwise it's the marvels of modern manufacturing, lol
 
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Let’s see one? I posted mine. Here it is again. No photo it’s just talk!
This is a true 0%. 7071 aluminum alloyed for the aircraft industry.

Fair enough, 7075 from stock. One has a machined magwell (not milspec) (note chatter) the other a broached magwell (milspec). Done on a 3-axis machine, so 8 setups. Just some slightly different prototypes I did last year but decided not to pursue further. But hey, they shoot great and I have the pride of making them from scratch.
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For all the money and time for getting this done right, I would suggest a Ghost Gunner 2.

Ghost Gunner 2

For under $2,500 you could build up 10 gorgeous lowers. That is the price of one really nice built up AR. Get you 80% lowers finished. 10 lowers is a lifetime supply for all intents and purposes. You can bury 10 lowers in a bunch of places for when the time is right.

If 10 lowers is enough, sell the Ghost Gunner 2 to the next guy and retire from the machine shop with a smile on your face.
 
What did you use for a broach?

I had access to a Ty Mills vertical broaching machine. The AR magwell broach was about 4 feet long. The company that I did it at is now defunct and their stuff was sold off. The machine I think went for around $70k and the broach itself for around $15k... needless to say you need to be cranking out lowers to make that money back.

But the process was you machined out about 90% of the magwell to a predefined shape, you then fixture the lower and the broach is pulled down and through creating the sharp corners of the magwell. The machined one I actually drilled out the "sharp" corners first using a super small diameter drill and then machined from there. The reason I drilled first was that such a small diameter drill would have deflected off the wall if I had machined out a huge pocket first.

In this regard, just pick up 80% lowers with broached magwells and follow Reptile's advice.
 
Fair enough, 7075 from stock. One has a machined magwell (not milspec) (note chatter) the other a broached magwell (milspec). Done on a 3-axis machine, so 8 setups. Just some slightly different prototypes I did last year but decided not to pursue further. But hey, they shoot great and I have the pride of making them from scratch.
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Nice! They look great!

Do I see.some G-code in there?

If your using a broach your talking the big time!

My magwell I defined the corners with a drill bit then hogged out 90% of it with a 7/8 endmill and I had to finish the rest of it with files!
If I had a broaching machine? That’s when I know I’d hit the Megabucks!
 
For all the money and time for getting this done right, I would suggest a Ghost Gunner 2.

Ghost Gunner 2

For under $2,500 you could build up 10 gorgeous lowers. That is the price of one really nice built up AR. Get you 80% lowers finished. 10 lowers is a lifetime supply for all intents and purposes. You can bury 10 lowers in a bunch of places for when the time is right.

If 10 lowers is enough, sell the Ghost Gunner 2 to the next guy and retire from the machine shop with a smile on your face.

These dipshits who make this type of equipment need to change the way they name them We’re are own worst enemies!
Naming equipment like this gives ammo to the other side big time! What the heck are people thinking?

For the price of that thing I could buy a nice used Bridgeport and have enough left for some tooling! A good used Bridgeport can be had for a grand with no DRO. I’ve seen them with decent DRO’s for around 1500. That way when your done you can keep it hone your skills and open your own backyard machine shop!
 
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For $2500 you can get a decent sized bench mill, tooling and a few 80% lowers - why buy a one trick pony when you can end up with a mill for the same price?
 
These dipshits who make this type of equipment need to change the way they name them We’re are own worst enemies!
Naming equipment like this gives ammo to the other side big time! What the heck are people thinking?

For the price of that thing I could buy a nice used Bridgeport and have enough left for some tooling! A good used Bridgeport can be had for a grand with no DRO. I’ve seen them with decent DRO’s for around 1500. That way when your done you can keep it hone your skills and open your own backyard machine shop!


Cody Wilson isn't a dipshit. He's making a very serious 2nd amendment and political freedom statement. He's put time, money and effort into building these machines because he believes that the government has no right to control your access to firearms. This is the same guy who built the 3d printable "Liberator" pistol. He's a pretty interesting guy.
 
OP- IANAL so I'm not going to comment on the legal aspects.
But as for the machining side, get a jig, it will make your life so much easier. You could use a dremel, or possibly even a router, but a good drill press is a solid investment for any shop. If you do any building, woodworking, fabrication, or even just a little DIY, you'll find yourself using it all the time. It does wonders for getting a perfectly square hole, and even just makes it easier to drill, especially through tougher materials.
 
For $2500 you can get a decent sized bench mill, tooling and a few 80% lowers - why buy a one trick pony when you can end up with a mill for the same price?
Technically not a one-trick pony, though it's talked about as such. The GG is a desktop CNC optimized for aluminum (I think the 2 can do steel now, too?) that happens to come with g-code for various lowers, most notably the AR-15.
 
A jig, a variable speed router and a drill press and 80% lowers are not hard to complete for anyone who is even slightly competent with tools. I have the Modulous Arms jig and it worked great, a couple of minor cosmetic issues with a couple of lowers (my fault, not the equipment) but all fully functional.
 
A jig, a variable speed router and a drill press and 80% lowers are not hard to complete for anyone who is even slightly competent with tools. I have the Modulous Arms jig and it worked great, a couple of minor cosmetic issues with a couple of lowers (my fault, not the equipment) but all fully functional.

I tell all my friends this. I even tell them they can borrow one of my jigs. I have the Modulous Arms and 80% Lowers jigs, done multiple lowers and none of them have any issues. I like the Modulous Arms jig better than the 80% for 2 reasons, but none that would prevent me from using it.
 
Nice! They look great!

Do I see.some G-code in there?

If your using a broach your talking the big time!

My magwell I defined the corners with a drill bit then hogged out 90% of it with a 7/8 endmill and I had to finish the rest of it with files!
If I had a broaching machine? That’s when I know I’d hit the Megabucks!

Access to the broach was a one time deal that I had the opportunity to play with, it was pretty cool but I wasn't allowed to take pictures because of ITAR or some BS. There is someone in the US that has a horizontal broach that will do it for people. You basically send it as a 70% and he broaches which makes it into an 80% (LOL) and then you can finish it to a 100%.

Here is some info for general interest purposes:

Broached AR-15 Lower Receiver - Willoughby, Ohio

If you check out this youtube link this guy will broach for you and his number is in the youtube video comments section:


View: https://www.youtube.com/watch?v=CY9Cb9YqOR4


If so inclined and you have the space older used mills are awesome and handy to have around the house (this is what you tell the wife)

As to worrying about registration, etc. I make mine more for the fun and challenge of doing new things. The bummer is the ones I make sit in my friends safe up in the free state of NH and I have to head north to shoot. Not in the mood to get jammed up down here.
 
Access to the broach was a one time deal that I had the opportunity to play with, it was pretty cool but I wasn't allowed to take pictures because of ITAR or some BS. There is someone in the US that has a horizontal broach that will do it for people. You basically send it as a 70% and he broaches which makes it into an 80% (LOL) and then you can finish it to a 100%.

Here is some info for general interest purposes:

Broached AR-15 Lower Receiver - Willoughby, Ohio

If you check out this youtube link this guy will broach for you and his number is in the youtube video comments section:


View: https://www.youtube.com/watch?v=CY9Cb9YqOR4


If so inclined and you have the space older used mills are awesome and handy to have around the house (this is what you tell the wife)

As to worrying about registration, etc. I make mine more for the fun and challenge of doing new things. The bummer is the ones I make sit in my friends safe up in the free state of NH and I have to head north to shoot. Not in the mood to get jammed up down here.


Nice! Yeah a bunch of time and $ went into that setup. I have an old verticle slotter/shaper at work and if been toying with the idea of doing a magwell with it. It's finding the time to make the 1/2 dozen or so single point tools I would need.
 

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I tell all my friends this. I even tell them they can borrow one of my jigs. I have the Modulous Arms and 80% Lowers jigs, done multiple lowers and none of them have any issues. I like the Modulous Arms jig better than the 80% for 2 reasons, but none that would prevent me from using it.

i've got the modulus jig and it is top notch . Modulus Arms | AR-15 80% Lower Receivers and Jigs . the insides of the ones i've done look like they were machined on a mill .
 
80%'s are interesting. And fun.

You have two sets of laws you have to be aware of, (and then you can choose to comply or violate).

I can take an 80% lower and complete it for my own personal use without violating any state law here in Georgia and without violating any Federal law.
Yet, the same actions violate CT law because CT says I'm not allowed to have any NEW AR's...

I'm not sure what the Massachusetts state laws governing your actions are, you'll have to figure that out, particularly with Maura's BS.

I can tell you this - the ATF says that YOU must do the work yourself. If I do the work for you, then I'm a manufacturer, and since I'm not licensed, and I'm not a FFL, I'm violating ATF regulations. They frown upon this.

My suggestion to you is to find a friend with the jig set who has his own 80% to do, go watch him do his, then do yours using his equipment while he watches/coaches. But do your research about what the ATF considers legal, they really don't have a sense of humor from everything I've read and heard about them.

I have a set of the jigs. I use a small milling machine to complete my 80%'s, but it can be done with a drill press and a router.

This is worth reading in-response to your point:

https://www.atf.gov/file/11711/download

My experience is, a gunsmith doesn't mind working on a home-built gun if you've already completed the State eFA-10, and the Federal Form 4473 in-advance of the work. If you haven't, then the gunsmith has to have the appropriate licensing to be a 'gun manufacturer', whereas they do these forms for you before they can transfer the 'project' back to you.
 
This is worth reading in-response to your point:

https://www.atf.gov/file/11711/download

My experience is, a gunsmith doesn't mind working on a home-built gun if you've already completed the State eFA-10, and the Federal Form 4473 in-advance of the work. If you haven't, then the gunsmith has to have the appropriate licensing to be a 'gun manufacturer', whereas they do these forms for you before they can transfer the 'project' back to you.

An 07 doing work for another 07 works under a variance. A gunsmith cannot engage in manufacturing at all.
 
Might be a stupid question. Asking for a friend who bought an 80% from a guy in a place; are the jigs universal? If he had no jig, could he "find" one somewhere and use it for his lower?
 
are the jigs universal?
Oh hell yes.
are they? some seem proprietary and come with certain manufacturers 80% lowers. but also, i'm sure there are 80%s out there exactly like the standard colt m-4 style receiver shape. the jig from a polymer 80 lower won't fit my buddies lower of another manufacture that came without one.
personally, i think it's useless to buy an 80% and not get a jig at the same time. that's being a "skinflint."
 
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