• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

80 % Lower receiver, Let me know your thoughts

Superlite17b

Superlite17b

Stugots
Full Member
Minuteman
Sep 26, 2012
28
0
Offshore oilfield
I recently ordered a jig and billet 80% lower receiver. For those of you who have successfully or unsuccessfully completed your lower let me know what you did or think or any tips, tricks etc. I do have a high quality drill press and access to some different milling equipment. Is it worth it to get an upper receiver for fitting purposes? I feel like I will get a better solid fit that way.
Yes I did a search, I found some stuff but I would like to know any up to date info.
Thanks
John
 
Take your time. Use step reamers to make your final hole sizes. Snap pictures and share with us your success!
 
Paste a sign above the mill or drill press that says, "You can always take more off, sneak up on the final dimension slowly".

80% are easy, but like everything else in life, the first one is the hardest.
 
  • Like
Reactions: JimLee
My plan is to sneak up and take the last off very slowly or by some sort of sanding procedure. As with most things on the internet there is an overload of info wether good or bad. I have a drill press with a Milling vice, not quite a mill but a little more than a drill press, I know the RPMs are not quite the same out of the press. Would I be better with a Polymer lower to start? Im not afraid to make a mistake and start over, new. What jigs have you all used? I am having second thoughts on the one I ordered.
 
if you can do it well, ok, but if it's a hack job don't feel bad, a completed one is easier to come by.
 
I am starting one now but have to lean on a relative in a shop to do it for me. I hate to ask for favors, but he has the equipment and said he can get around to it. Wish I had one to show him already finished so he can understand that will be done with that area. It would be nice to have a finished dimentional drawing to show him of what the final part should be since we have no jigs for these .308 DPMS style lowers yet. I guess its all a matter of who you know with equipment to get it done right. I would assume that after the maching the lower would have to be sent out for engraving for a model, caliber, fire/safe indicator etc. It might be cheaper to buy one already done and pay the FFL fees. I'll advise when its finally done.
 
I am starting one now but have to lean on a relative in a shop to do it for me. I hate to ask for favors, but he has the equipment and said he can get around to it. Wish I had one to show him already finished so he can understand that will be done with that area. It would be nice to have a finished dimentional drawing to show him of what the final part should be since we have no jigs for these .308 DPMS style lowers yet. I guess its all a matter of who you know with equipment to get it done right. I would assume that after the maching the lower would have to be sent out for engraving for a model, caliber, fire/safe indicator etc. It might be cheaper to buy one already done and pay the FFL fees. I'll advise when its finally done.
 
Last edited:
Be care full and don't hit the threaded ring the buffer tube screws into with the spindle when you make your final cut for the slot the rear upper rear lug goes into.
 
according to batf you have to cut the receiver. It is illegal to have someone cut it for you.
It is very easy. The first one i did came out a little rough on the inside but it works flawlessly. The second is mirror smooth and works flawlessly as well.
i would recommend getting a lower parts kit it will really help with final cuts. Also i would recommend at this time to order either anti roll pins or anti walk pins. They really help if the hammer or trigger hole walk a little bit.
 
  • Like
Reactions: Soulezoo and JimLee
Thats very interesting. I was not aware that you actually had to do it yourself. Oh well, will have to buy a jig now and put the drill press to work. I'll have him make up some type of vice or fixture for holding the workpiece though.
 
harbor freight sells a mill attachment for drill presses. let me find it. 6" Cross Slide Vise
its very similar to this. I did 2 lowers using only this a few drill bits and stopped at a machine shop supplier and got a 17 dollar 3/8's 2 flute mil bit 4 inch's long.
 
If its a computerized machine, anybody can program it as long as you hit the start button; or if its manual, he can babysit you and guide you while you physically make the adjustments.
 
I was just looking at the harbor freight mini milling machine. I have a drill press and an XY vice or cross slide vice, but I drill press is not the optimal tool for milling, the spindle is not meant for side loading, but I think if it is taken in small bites it will be okay. I have a jig and have been watching some of the better movies on youtube. Plus my jig and lower came with very detailed directions and measurements. It looks like its is almost idiot proof if you take your time and go at it slow and keep the metal cool as possible. I plan on starting tomorrow with the drill press and will try to get pictures that show the process.
 
Melsy said:
harbor freight sells a mill attachment for drill presses. let me find it. 6" Cross Slide Vise
its very similar to this. I did 2 lowers using only this a few drill bits and stopped at a machine shop supplier and got a 17 dollar 3/8's 2 flute mil bit 4 inch's long.
Click to expand...
Wondering what size and brand drill press you are using if you don't mind. You can PM me the info if you want. Looks like I am just down the road off of 1097.
thanks
 
its a really old one. i ran it on the slowest setting and bit very very slow. Did your jig have the drill plates with it or is it single stage with just the opening.
 
It is a newer design than the one I think you are talking about, it has a moveable plate and dual openings on the top, you start with the lower in one way, drill 16? holes and the trigger selector holes etc, then spin the lower the other way in the jig and use the removable plate and the existing opening on that side of the jig. it is a good, simple design as far as I can tell.
 
I have a jig and harbor freight mill. I messed up my first one as my vise wasn't squared up well enough and I ate into my jig plate trying to go too fast. got into the trigger pin hole area enough that I dint feel comfortable enough to build it. expensive mistake as it was a custom engraved 80% that I stupidly started with. got 3 more that aren't engraved but its currently too cold in the garage to mess with.

I plan on making at least one of these before I get another engraved for my sbr build. I had vaderspade engrave the 80% lower. I p[lan on just stamping my ssn into these with some steel number punches.
 
it makes it mine I guess.

I got into 80% lowers mostly as a way to have a true full custom lower with my dob or ssn as the serial number and engravings that mean things to me. going to have one engraved for my brother as well who just got selected into SF and when he comes down, he can mill it out on my equipment.

it also looks like a legitimate lower with a serial number to prevent the dumb questions at the local range.
 
Last edited:
I'd go with date of birth, myself. Just don't like flashing the ssn around anymore than necessary.
 
For aluminum you should spin the 3/8 endmill at 2100ish RPM. the 1/4 should be at 3200RPM, but it should do just fine at the 2100. Yes it is fast but just remember to feed it slow. The high RPM will give you a much better finish. Also, there are two ways to mill: climb milling and conventional milling. Conventional milling requires less spindle power and is recommended for manual machines especially ones that have a lot of backlash in the table movement. Climb milling does require more spindle power and requires a tight and sturdy table (most CNC work is done climb milling), but it leaves a MUCH better surface finish. PLEASE LOOK UP CLIMB VS. CONVENTIONAL MILLING AND SEE WHICH ONE BETTER SUITES YOUR SETUP! Also make sure your final pass is .003 to .005, any less and it usually just rubs the material instead of cutting it. Make sure you have a way to get the chips out while you are machining.

The most important thing, though, is to know your setup and how it works. Make sure you are comfortable using it and have a little confidence with it. You want to know that when you turn the handle .005" that it will actually move .005" Don't be distracted by music or any other outside sounds, the sound the endmill makes while cutting will tell you everything you need to know.

FYI, I am a machinist by trade doing both manual and CNC machining. I do have a completed 80% lower that is now a functioning rifle so yes, I have done this before.
 
Last edited:
retiredcop said:
Thats very interesting. I was not aware that you actually had to do it yourself.
Click to expand...

The reason is techenly unless the other person has a FFL they arnt aloud to so much as clean your firearm. Technically...

To get around that sell the 80% to your relative for a $1 then buy it back. That's how I do it when people need my help with stuff.
 
In round figure terms how much does it run to send a lower out for engraving? I have a set of stamps I could use, but they are a little bit on the small side. I was thinking about having it engraved with my name serial #0001, a born on date and getting it ceracoated.

Thanks for the info on the machining particulars and vice. This can be a fun project when it gets a little bit warmer in the garage. I still have my dads old but very high quality drill press.
 
Not sure which jig you have but I found them to not take enough out to fit the trigger & hammer in.

So when done, and before you tear it all down, check to make sure the trigger & hammer will fit. That way, if you need to take a few thou off the sides, it is easy to remove the top plate on the jig and do that.

Also, have the upper handy to check and make sure it will fit. Sometimes in your effort to be careful at the rear you will not take enough for some uppers at the rear lug.
 
Melsy said:
according to batf you have to cut the receiver. It is illegal to have someone cut it for you.
It is very easy. The first one i did came out a little rough on the inside but it works flawlessly. The second is mirror smooth and works flawlessly as well.
i would recommend getting a lower parts kit it will really help with final cuts. Also i would recommend at this time to order either anti roll pins or anti walk pins. They really help if the hammer or trigger hole walk a little bit.
Click to expand...

Where is this referenced from? The BATF "regulations" can be very grey and vary from region to region.

With most firearm modifications you only need an FFL if you modify the weapons as a business, i.e. for profit. I don't know why it would be any different for an 80% lower.
 
California has shut down all of the 80% build parties and shops because they are under the opinion that the person has to program the CNC mill and perform all the work themselves. Now that is their warped interpretation of the laws, so just know your local areas interpretation since there isnt any case law yet.
 
  • Like
Reactions: GONE BAD
California is also corrupt and the state constitution doesn't have a right to bear arms. As bad as this sounds, just don't get caught doing anything you shouldn't.
 
Regarding putting your SSN on the lower: its a personal choice obviously. However, if the weapon gets stolen later the cops cannot plug in your SSN to find the owner. But they can plug in a driver's license number and get your name, address etc.
I don't know if the new LEIN systems will let them put the rifle in them being that it does not have a manufacturer etc. They MIGHT be able to do that and use the SSN as a serial number, but it could not be done before I retired.
 
I'm using the one from Lockestone it's quality but if your magwell is flared out a lot at the bottom it may not fit. It's simple to use and will last if you don't cut it. Plus it's only 80$ or so. Compared to some of the others. Plus their customer service is top notch.
 
coryhenry said:
California has shut down all of the 80% build parties and shops because they are under the opinion that the person has to program the CNC mill and perform all the work themselves. Now that is their warped interpretation of the laws, so just know your local areas interpretation since there isnt any case law yet.
Click to expand...
But California companies can ship 80% lowers out of state.
 
Yes California companies can produce 80% lowers and ship them because they are still a block of metal. But completing the lowers is where the state skews the law to fit their purposes.
 
A couple of 80% questions...Can one be built and designated for pistol use and is there a maximum number of completed lowers you can machine for personal use? I can't seem to get a straight answer. I want to be within the law obviously because I wouldn't ask the question otherwise.
 
dang472 said:
A couple of 80% questions...Can one be built and designated for pistol use and is there a maximum number of completed lowers you can machine for personal use? I can't seem to get a straight answer. I want to be within the law obviously because I wouldn't ask the question otherwise.
Click to expand...

Yes you can build one as a pistol but it must first be built as a pistol and not a rifle. According to this law, if you first build it as a pistol, you can then change it to a rifle and back to a pistol whenever you please (be careful of NFA laws when changing, don't let it become an SBR). You can't take an AR rifle and convert it to a pistol.

There is no limit to how many you can have.
 
Here is a build that i did last week, still need to anodize and put cerrakote finish on it




Details: ares armour 80% lower, cmmg lpk with a ACT trigger replacing the factory, MOE buttstock, JP spring and dpms 308 buffer

Upper- DPMS, BCG nickel boron coated BAT barrel extension, GM 1-11.25 gunsmith blank chambered with PTG .308 reamer go +.002 headspace, takeoff armalite handgaurd and gasblock, flash hider


Since DPMS are not compatible with Armalite handgaurds, I had to make a custom barrel nut...


Since I did not have access to my normal AR 10 tools I had to make a quick and dirty barrel extension wrench and barrel nut wrench...

 
Last edited:
  • Like
Reactions: Blue Sky Country
so have been using a router with a mill end bit, and a jig. taking 1/16" or so passes is very time consuming. does anyone just drill out as much as possible in a drill press and then clean up with a router? if so, what diameter/type drill bit are you using? any router time savings is appreciated.
 
  • Like
Reactions: Blue Sky Country
I decided to finish an 80% just before the 2016 election (go figure). Anyway it didn't work out so well.

I got to talking with acquaintance and he said he distroyed his first attempt.
Seen him late last year and he showed me his latest one. It looked like a factory one!
He said he used a jig with a router.

I was using a Anderson jig and drill press.
About a month ago I was thinking I'd get another one but I figured I needed to work with my first one through conpletion before I started another, just for experience.
Well I got the old one out and started working on it.
Couple of hours later it was starting to not look so bad.
Put a trigger in it, a safety, and put an upper on it and it's just fine.
I'll build more and my factory lowers will go down the road.
Once again not a good time to be buying metal with serial numbers. Just saying?
I live in a socialist state. So sad!
 
  • Like
Reactions: Blue Sky Country
I use an 80% arms jig with a Dewalt plunge router. Works pretty good. I trashed the first one (kinda expected it), but the others I have done came out just like you buy them. Hardest part actually ends up being the pin holes, but their newest jig has a very long drill bit guide to help. Don't drink while milling, at least I know I shouldn't.
 
  • Like
Reactions: AMGtuned and Blue Sky Country
davsco said:
so have been using a router with a mill end bit, and a jig. taking 1/16" or so passes is very time consuming. does anyone just drill out as much as possible in a drill press and then clean up with a router? if so, what diameter/type drill bit are you using? any router time savings is appreciated.
Click to expand...

When I wrote my program on a cnc mill, I choose to run a drill bit first to remove a good portion of the material, a drill bit's maximum material removal (MMR) is more efficient than a endmill's MMR often times, plus it is much cheaper.....To answer your question lay out your holes such that they do not "break through" the webb of the adjacent hole and use a drillstop to control your depth if you are not using a milling machine....
 
I didn't read everything here but those that posted 'intent' could just delete those posts and the thread would still have the necessary advice.

OR, just tell the BATF to pound sand.

Your choice but discussing illegal activity is usually bad for a gun forum.
 
I've done a half dozen now. I use an old Ares Armor jig (warning! The folks that took over Ares Armor and renamed it are unethical douchebags... do not do business with them!) Anyway 80% company uses the same and are gtg.
I use drill press and milling vice. There's enough good advice above that I won't repeat.
What I will add is BE PATIENT!! And measure precisely and often.
 
Not trying to threadjack here, but this does raise some interesting questions regarding 80% lowers. Since the starting point is, by definition, just an oddly shaped chunk of aluminum and the final product is a firearm, is a Form 1 required?

If not, what's to keep a person from turning an 80% lower into an SBR? Or installing a full auto FCG, for that matter?

Asking for a friend.
 
Last edited:
@BurnOut GCA'68 provides for an individual to make their own no form 1 required, read the ATF FAQ's that address this issue. You may make an 80% into a SBR after your paperwork is approved and you have a stamp back, if you are a 02/07 you may form 2 a 80% into a post 86 MG, either of these is the same as starting with a 100% receiver, the only difference is what you put on certain lines of the form and how many different markings are on the receiver.
 
skinnj1 said:
@BurnOut GCA'68 provides for an individual to make their own no form 1 required, read the ATF FAQ's that address this issue. You may make an 80% into a SBR after your paperwork is approved and you have a stamp back, if you are a 02/07 you may form 2 a 80% into a post 86 MG, either of these is the same as starting with a 100% receiver, the only difference is what you put on certain lines of the form and how many different markings are on the receiver.
Click to expand...
Excellent! I... uh, I mean, my friend... appreciate the info!
 
  • Like
Reactions: Rocketvapor
@BurnOut

Just to be crystal clear making your own Title 1 is OK from a fed point of view, read ATF FAQ's, be careful of statel and local regs that may be more stringent.

Title 2 (NFA) still require you to do NFA forms and have all the same restrictions (no post 86 full auto except leo/military/dealer samples) as any other Form1/Form2/Form5 etc. As the case may be...
 
You must log in or register to reply here.

Similar threads

I
80% lower
Replies
2
Views
341
ironman56
I
JohnDeereGuy1996
Geissele GFR Maritime Reconnaissance 6mm arc write up and review
Replies
52
Views
3K
BulletWithBirdWings
BulletWithBirdWings
Halfnutz
CMP M1 Advanced Maintenance Course-Build your own "Expert Grade".
Replies
8
Views
405
Halfnutz
Halfnutz
Bcamos
DAKA Grid Organizer - My thoughts
Replies
11
Views
979
LuvDog
LuvDog
baker72
USMC DMR McMillan Black M14 Stock 1 of 4
Replies
7
Views
628
baker72
baker72
Top Bottom
Back