AR15.Com Archives
 80% complete lower receiver build
crcrichton  [Member]
1/20/2010 10:17:45 AM EST
Has anyone done one of these since 12/1/09? Apparently spec's have changed and instead of threading the buffer the fcg well is solid. The building process now involves drilling and milling out that well in addition to the previous norm of drilling the necessery holes in the receiver blank.

Is this more difficult that the previous versions? Any comments or problems anyone has encountered? I'd like to try one, advice or suggestions?

Thanks.
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RDTCU  [Team Member]
1/20/2010 10:22:59 AM EST
Buy your 80%'s from Tactical Machining, i've done a few of them.
Much easier than before (less jigging / steps), but there is more milling to do.
Before the requirements changed, i used AR15PLUS.com, but now they've caught up with times and are selling compliant lowers.
They're just twice as much for more work and lower quality, in my opinion...



Mill the FCG pocket, and rear lug pocket
Mill the trigger slot
Drill the TWO holes (trigger/hammer)

and you're done!

They're pretty nice too...
crcrichton  [Member]
1/20/2010 11:00:47 AM EST
They are wonderful!!!! Just placed my order.
RDTCU  [Team Member]
1/20/2010 11:03:27 AM EST
Sweet!

Have fun, (and take your sweet time...)

Do you have an AR Lower print? Comes in handy...
If not, got here and download from the "Blueprints" section: CNC GUNS
crcrichton  [Member]
1/20/2010 5:08:25 PM EST
Do they need to be anodized after we've finished the build?
RDTCU  [Team Member]
1/20/2010 5:22:16 PM EST
I've never taken one to be anodized, but you could. I usually soda-blast, acetone and Duracoat. Works just fine on the blasted surface, including inside the pin holes. If you want to have it anodized you'll have to be there or have a firearms anodizer do it (once you complete it, it's a firearm and must be transferred as such, unless you're actually there)... Some people have had luck with the home-anodizing kits, but i've never played with one...
crcrichton  [Member]
1/21/2010 5:13:31 AM EST
Silly me, it's in the web site, they're anodized at the factory. Need to read all the stuff before I post.
RDTCU  [Team Member]
1/21/2010 5:41:12 AM EST
Originally Posted By crcrichton:
Silly me, it's in the web site, they're anodized at the factory. Need to read all the stuff before I post.


Well not sure what you mean, finished or 80%...

Finished, stripped lowers are factory anodized.
80% lowers are bare aluminum when you get them...
PraesulPresul1  [Member]
1/21/2010 8:47:48 AM EST
Originally Posted By crcrichton:
Silly me, it's in the web site, they're anodized at the factory. Need to read all the stuff before I post.


Anodizing is surface treatment so your milling would remove it in those areas so the above poster is right.
crcrichton  [Member]
1/23/2010 1:45:07 PM EST
I ordered the tools, bits and mill and they've come in, downloaded the blueprint and printed out a blownup copy, I've got a couple of cans of wd-40 for cutting fluid. And, have gone through the tutorial on cnc guns website. I'm ready!!

Thank you all for your advice, I''ll update this as I go along...
fdv99  [Member]
1/23/2010 5:16:03 PM EST
Does anyone know when tactical machining will have more 80% lowers in? I emailed them about it but haven't heard back yet.
TXGUNNER308  [Team Member]
1/23/2010 5:36:16 PM EST
educate me...what is the benefit of this? seems like a lot of work for something i can buy 100% complete.
RDTCU  [Team Member]
1/23/2010 6:22:04 PM EST
Originally Posted By crcrichton:
I ordered the tools, bits and mill and they've come in, downloaded the blueprint and printed out a blownup copy, I've got a couple of cans of wd-40 for cutting fluid. And, have gone through the tutorial on cnc guns website. I'm ready!!

Thank you all for your advice, I''ll update this as I go along...


I'd trade the WD40 for some cutting/tapping fluid or some cheap gear oil.... WD40 doesn't make the best cutting fluid, it's too light and vaporizes quickly.


TXGUNNER,
It's the idea of completing something yourself for some, and the lack of paperwork for others... If i'm going to try something crazy with a design, which i do a lot of, i don't want to ruin a registered firearm to do it. (Such as the bufferless pistols or the .45 lower i built for $80, instead of $300 for a factory .45 lower...)
RDTCU  [Team Member]
1/23/2010 6:22:34 PM EST
Originally Posted By fdv99:
Does anyone know when tactical machining will have more 80% lowers in? I emailed them about it but haven't heard back yet.


Call them, they've always answered for me and that's how i ordered my lowers...
shrikefan  [Team Member]
1/23/2010 7:05:45 PM EST
IIRC kerosene works good on aluminum.
slappomatt  [Team Member]
1/23/2010 7:39:39 PM EST
one reason to do it and the reason I will be getting one in the near future is to get around asinine laws. In Ca you can only buy handguns on approved lists. there are no AR pistols on these lists so if you want one you have to jump through alot of loopholes to get a pistol registered lower. The easiest to do BY FAR is to build an 80% lower yourself.
gr8jrny  [Team Member]
1/24/2010 7:21:47 AM EST
Just wondering what mill people use, I have heard not to get from Harbor Freight, and that Grizzly is good, but what model say from Grizzly is best for this job. I don't intend to use it for things other than firearms and that size or scope? Any recommendations will be appreciated.
RDTCU  [Team Member]
1/24/2010 8:58:45 AM EST
Originally Posted By gr8jrny:
Just wondering what mill people use, I have heard not to get from Harbor Freight, and that Grizzly is good, but what model say from Grizzly is best for this job. I don't intend to use it for things other than firearms and that size or scope? Any recommendations will be appreciated.


I've got a full-sized Bridgeport mill, but i've heard good things about the Grizzly.... If you're using the smaller mills, i would recommend the 80% jig from Tactical Machining as well, just to simplify the jigging...
SR712  [Team Member]
1/24/2010 9:26:45 AM EST
Harbor Freight and Grizzley are the same machine, made by Seig (China). Whichever you can get the best price + shipping (these are heavy). HF was free shipping when I bought mine. CNC Gunsmithing has a forum all about machining lowers, etc.
gr8jrny  [Team Member]
1/24/2010 10:03:33 AM EST
Thanks for the tips on mills
crcrichton  [Member]
1/24/2010 11:09:25 AM EST
Thank you for the heads up on cutting fluid, I'll be looking into that.

Good question concerning 'why go to all the trouble for something I can buy.'

I can only speak for myself and two of my friends. We just finished building 3 ak's from Romanian parts kits. We bought the receivers but learned alot about furniture refinishing, riviting, knocking out stubborn barrel pins, blueing and pressing/installing barrels.

When we finished the builds we looked at each othe and said that was fun lets not stop now. So this 80% ar receiver is our next project. We're doing it for a sense of accomplishment, as a hobby and for the pride of doing something not many other people have done. We're definitly not saving money.

Just my two cents, thank you everyone for your remarks.
dangerdan  [Team Member]
2/15/2010 11:53:27 PM EST
Originally Posted By RDTCU:
Buy your 80%'s from Tactical Machining, i've done a few of them.
Much easier than before (less jigging / steps), but there is more milling to do.
Before the requirements changed, i used AR15PLUS.com, but now they've caught up with times and are selling compliant lowers.
They're just twice as much for more work and lower quality, in my opinion...

http://www.tacticalmachining.com/images/372_247_80-lower.jpg

Mill the FCG pocket, and rear lug pocket
Mill the trigger slot
Drill the TWO holes (trigger/hammer)

and you're done!

They're pretty nice too...


You need to drill for the buffer tube retainer pin also.
RDTCU  [Team Member]
2/16/2010 2:38:39 AM EST
Originally Posted By dangerdan:
Originally Posted By RDTCU:
Buy your 80%'s from Tactical Machining, i've done a few of them.
Much easier than before (less jigging / steps), but there is more milling to do.
Before the requirements changed, i used AR15PLUS.com, but now they've caught up with times and are selling compliant lowers.
They're just twice as much for more work and lower quality, in my opinion...

http://www.tacticalmachining.com/images/372_247_80-lower.jpg

Mill the FCG pocket, and rear lug pocket
Mill the trigger slot
Drill the TWO holes (trigger/hammer)

and you're done!

They're pretty nice too...


You need to drill for the buffer tube retainer pin also.


Not on the ones i ordered....
and from their website:
"The operations left to be completed are as follows: fire control group, trigger pin, hammer pin, trigger slot."
dangerdan  [Team Member]
2/16/2010 3:45:33 AM EST
Sweet. I'm hoping to do this when I get home. I hope they have some .308 80% er's in stock soon.
GLADIO  [Member]
2/16/2010 4:34:25 AM EST
I've read somewhere on the ARFCOM that some alphabet agency loves to wander through the customer database of 80% lowers sellers..
st33ve0  [Member]
2/16/2010 4:43:45 AM EST
What jig are you guys using for your milling?
eliteAR  [Member]
2/16/2010 5:24:22 AM EST
I buy my 80% AR15 and AR10 from www.ar15jigs.com they also have the jigs.
RDTCU  [Team Member]
2/16/2010 6:26:57 AM EST
Originally Posted By st33ve0:
What jig are you guys using for your milling?


I just use my mill vise and some 1-2-3 blocks, but i'm using a bridgeport and not a dremel and a drill press...

Originally Posted By eliteAR:
I buy my 80% AR15 and AR10 from www.ar15jigs.com they also have the jigs.


That's a pretty good price for billet "75%" lowers, but a good bit more work. If you've got a mill, it wouldn't be bad though...
JimM44  [Member]
2/16/2010 8:57:55 AM EST
Tactical now also sells their own jigs for finishing these using a drill press.
Russ4777  [Team Member]
2/16/2010 11:54:33 AM EST
Originally Posted By st33ve0:
What jig are you guys using for your milling?


I used another "factory" stripped receiver clamped next to it as a jig to make this one. Did it on a good drill press with a 2-axis slide vise.

st33ve0  [Member]
2/16/2010 12:28:44 PM EST
I have access to manual and CNC mills as well as knowledge on how to use SolidWorks so that's why I asked, I'd really only need the best way to clamp the receiver without marring the finish. Thanks guys
RDTCU  [Team Member]
2/16/2010 12:41:51 PM EST
Originally Posted By st33ve0:
I have access to manual and CNC mills as well as knowledge on how to use SolidWorks so that's why I asked, I'd really only need the best way to clamp the receiver without marring the finish. Thanks guys


I'm partial to Solidworks as well, use it everyday.
As far as marring the finish, there IS no finish, until you finish it
I usually clamp up on the grip triangle area to mill the FCG pocket, since it's fairly solid, and then use aluminum blocks to clamp the receiver in the mill vice sideways to drill the trigger and hammer pins.
st33ve0  [Member]
2/17/2010 8:14:16 AM EST
Originally Posted By RDTCU:
Originally Posted By st33ve0:
I have access to manual and CNC mills as well as knowledge on how to use SolidWorks so that's why I asked, I'd really only need the best way to clamp the receiver without marring the finish. Thanks guys


I'm partial to Solidworks as well, use it everyday.
As far as marring the finish, there IS no finish, until you finish it
I usually clamp up on the grip triangle area to mill the FCG pocket, since it's fairly solid, and then use aluminum blocks to clamp the receiver in the mill vice sideways to drill the trigger and hammer pins.


Yeah, SolidWorks is flat out awesome. I'm not the best at it, but I can do most things very well. It's fun just designing widgets and such :D
Bllade  [Member]
2/17/2010 8:39:38 AM EST
Me and my buddies have built over 10 AR's from Tactical Machine 80% lowers. We started using the jig from CNCGunsmithing and a drill press but then I bought the HF mini mill (Seig x2 clone). I added a DRO to my mill and now can machine a lower in about 2 hours using the fixture and dimensions I got from the ray-vin tutorial.
You can not go wrong using Tactical machine's 80% IMHO
wallym777  [Member]
2/17/2010 2:50:26 PM EST
Russ477, is your finish anodized, and if so, how did you do it or did someone else. It looks really good. I am working on an 80%, no idea on the finish.
Russ4777  [Team Member]
2/18/2010 6:18:27 AM EST
Originally Posted By wallym777:
Russ477, is your finish anodized, and if so, how did you do it or did someone else. It looks really good. I am working on an 80%, no idea on the finish.


No this gun is not anodized. Anodizing would be the best way to go, but to save some $, I sand blasted both the upper and the 80% lower then really carefully coated them with Norrell's MolyResin. After the oven cure this stuff is amazingly tough and resistant to all normal gun cleaning solvents. Even MEK won't bother this finish. It's available in a bunch of colors, but I went with the traditional matte black. Very happy with this finish. Cheap, quick, and easy.

Here's another pic of the whole gun from the other side.

wallym777  [Member]
2/18/2010 11:14:55 AM EST
Russ4777

Thanks for the info, have never heard of the product, nice to have a good option.
Shermantor-AR15  [Member]
2/18/2010 2:08:08 PM EST
OK this is peaking my interest, so I have a few questions for now.

1. The Mini-Mill someone mentioned from HF, could you link it? or is this it? Harbor Freight

2. Would the Mini-Mill work on Titanium 80% lowers? I'm sure it would be hard on the cutting tools but still wondering.

3. Since you are the maker could you have them engraved while they are 80% with serial Numbers and your info?

4. Can you send it off to be anodized? you are really only sending your lower to get done and back to you again.
JustKeepSwimming  [Team Member]
2/18/2010 2:50:45 PM EST
Originally Posted By Shermantor-AR15:
OK this is peaking my interest, so I have a few questions for now.

1. The Mini-Mill someone mentioned from HF, could you link it? or is this it? Harbor Freight

2. Would the Mini-Mill work on Titanium 80% lowers? I'm sure it would be hard on the cutting tools but still wondering.

3. Since you are the maker could you have them engraved while they are 80% with serial Numbers and your info?

4. Can you send it off to be anodized? you are really only sending your lower to get done and back to you again.


Here is a good look at the HF style and grace in design and construction, portrayed in great detail:

Home Gunsmith Forum

I didn't check to see if it's the same model you're looking at, but the author details some of the many problems that can and will rise up and bite you in the butt if you buy one of the HF machines and jump right into machining lowers.
TANGOCHASER  [Team Member]
2/18/2010 4:18:15 PM EST
Posted by GLADIO:
I've read somewhere on the ARFCOM that some alphabet agency loves to wander through the customer database of 80% lowers sellers..


The ATF has no legal right to access 80% lower sellers records without a warrant.. The sellers do not have an FFL and not subject to the oversight of the ATF without a warrant.

They do however have a say in determining which partially machined lowers are firearms and which are not.
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