I'm not sure the best way to do this without expensive equipment. I got a set of metal stamps but I'm afraid to use them, because they're really hard to position, and if you had to hammer twice (to deepen the impression) it would give people the false impression that the serial number/marking has been altered... not good. (it will leave a double strike, which many people will think it was altered)

I heard of etching or whatever but I am not familiar with how this works.

Engraving would be ideal but then it requires expensive equipment (expensive CNC mods to my mill for example).

What is the legality of sending it to someone to have it engraved? would they require a manufacturer's license to do this?

Find a trophy shop and ask them if they will engrave the lower.  They might be willing to do a finished lower or be able to put a fancy logo on it for you.

If you have done the milling, it is a  firearm and all rules apply.  If you haven't done any millings, its a paperweight.

If you hand carry it to a shop, they should be able to do the work without any special license, however, check your local laws.

In the past I've found aluminum to be fairly easy to stamp with steel dies, one strike leaves a pretty good impression that doesn't make people think the number was altered, but for steel it's a much bigger problem as multiple HARD strikes with a heavy hammer was required to leave any impression at all, and the multiple strikes made the mark ghosted, which made people think that the number had been altered....

I heard someone etching them, how does it work?

Try this

Look if you aren't going to be helpful then don't say anything. I'm sick of the "let me google that for you" link.

For your information googling doesn't always produce useful result. Youtube videos are full of inaccuracies and even dangerous advise (when it comes to anything that burns or explodes). Googling produces a bunch of forum posts that aren't always useful.

Why engrave and mark the lower in any way? What if someone (let's say a cop) sees it, and thinks it's one of those guns with modified serial number and doesn't know that guns without serial number exists? Do we have to, no. Are there guns without serial number, yes (those made before the 1968 gun control law, which I think very few AR's are). Most do it to avoid this kind of trouble.

Stamp them using your stamp set. Do it on the pistol-grip tang (hidden by pistol grip when assembled). It's easy to align the stamps in this location by resting the stamp shank against the flat area of the receiver which is at a right angle to the side of the tang.  Support the opposite side of the tang on a wood block and you're ready to smack it.  I also write the serial number in paint pen on the buffer tube so it is covered by the buttstock but easily accessible. That way you don't have to pull the pistol grip off to verify the serial number.

How can it have a modified (defaced) serial number if it never had a SN to begin with? There is no law that requires you to put a SN on a homebuilt unless you are going to transfer it. What is he going to charge you with?

First hit on a google search:

How To Electro-Etch Solid Metal

Complete with step-by-step instructions....

Second hit:

Create custom etched aluminium (aluminum) art

Third hit, right here on AR15.com....

DIY- electro-etching: simple, do-able, custom engraving.

Guess what, google actually works.....

If you put a serial number on a weapon it should follow the rules for a serial number, which means it has to be visible without disassembly.

Your in Texas.

Relax.

I live in Commifornia and I have never been hassled by a LEO about my
lower not having a serial.

But if you must.

Send it out before any machining while it is still an 80%.
No hassle because it is an 80%

And get a custom engraving

Send it to molon labe LLC in Arizona. They do deep laser engraving for $25 + $10 shipping.  They have FFL and engraved my finished receiver no problem. Took about a week from the time I shipped it to them.

I'll think about it. Perhaps I'll just stamp it with a stamp, aluminum seems soft enough.

The other problem is anodizing it... I found out there's someone in Austin (maybe not reachable by bus though) that will cerakote it... do you think that's a good alternative to anodizing? I just do not have the means to sand blast it at the moment.

Just buy a 100% receiver. Problem solved


And do more research on 80%s as to what
you can do. Cannot do.
Must have and what it does not need.

You can find cerakoting services offered on ebay for $40-45. Again, make sure they have FFL. I personally went with Aluma Hyde spray can. It actually came out pretty good.

I, too, almost got all caught up in the 80% game... and then came to my senses and bought a bunch of <$50 Anderson lowers, mil spec.
At first I was all about doing it myself... but then realized how much cheaper and better they are done from the factory.
Of course the "off the books" thought hit me... until I realized that boating accidents happen and things get "lost".
Just my .02

That being said, I TOTALLY get the "do it yourself" satisfaction thing (as I'm one of those guys too). But for receivers... just doesn't seem to make economical (nor finish) sense to me.... at THIS time.

Since it isn't REQUIRED to have one I can do it however I want.  

It's mainly avoiding unwanted attention from cops who doesn't know that making firearms is legal and that a serial number is not required. For all they know making guns is illegal...

By the way I tried stamping the pistol grip tang to see how it work... with my light hammer it's not going to work (barely any mark on first strike, double mark as soon as I make a second strike)

Just like if they saw a gun wrapped in duct tape they'd assume it was illegally modified or whatever and will take it, then let the labs determine that it was legal in the first place.

I'll definitely give the spray can options a try but it seems that sand blasting is required for any finish to stick, and I don't have a blast cabinet. Is there a way to "sand blast" it without a cabinet? You know for example tumble it in a drum full of sand...

By the way as far as cost goes, yea it's not going to make any sense but these days it seems AR's are getting cheap, with Tactical Machining selling them at 29 dollars each. Makes 0% forgings obsolete. I'll have to thank Obama for this.

FWIW, the trophy shop engraving option is probably going to be your best bet (while still in 80% form).

While the finish work will likely be a combo of 300-600 grit sandpaper/emery cloth, acetone bath, and
either alumna-hyde/cerakote/duracote spray on finish...

It can be done with a minimum of tools and fuss, just take your time and follow the youtube video's...

Just remember it's not a firearm yet it just a chunk of metal...or its just a really expensive/nice quality
air-soft frame

Good luck.

Yes, there is, you can buy a cheap "portable blasting kit" and blast outdoors.

Just wear gloves and a mask, and keep it pointed away from your car....

I realize that "sand" blasting is sort of a generic term, but if you are going to use one of those total loss type outdoor blasters with sand be sure to wear a real respirator not just a dust type mask.

silicosis is real. Aluminum oxide is a far better choice all the way around.

Sandblasting is not required for Aluma Hyde to adhere properly. I used a 220 grit sandpaper to 'rough up' the surface of the receiver. I then cleaned it up with 99% Iso and sprayed it. If you're going the Aluma Hyde route, make sure you get a pack of extra spray nozzles. They get clogged up very fast. I'm talking about after a min of spraying, the nozzle will clog up and will start to splatter. So extra nozzles are required. Brownells sells a pack of 10 or 12 for around $4 I believe. Oh, and don't forget to shake the living hell out of the can before you spray and in between coats. I only put on two coats and it looked good.

Just saying.
If I were to build an 80%.
After completion it will make one or two range trips for sighting and functionality then it will most likely lost in a tragic boating accident.
I have another AR for fun time and HD.

As someone said above, suggesting a shop engrave a number or even finish it for you.... Not legal for them to do so. They'd be manufacturing at that point. Now engraving a number BEFORE it is finished. Very grey area, though the ATF would probably get pissed. The only benefit to putting your own number on an 80% lower would be identification in the event of a theft and filing a police report. If you did this, I suggest removing the pistol grip and using a dremel to engrave it yourself on the aluminum under the grip. It would be obvious YOU did it and did NOT alter a previously engraved and registered number. If not under the grip, then somewhere no company will ever place a number. Inside the mag well for example. On the upper maybe. However, under the grip is not visible and would likely not be altered or ground off if someone stole it.

However, if it's stolen, there's no number on it, it shows up at a crime scene, and you filed a police report as an 80% with no number. They'd surely find your prints on it knowing it was yours that was stolen and used in the crime, and also clearing your name.

Bottom line as I've read in ATF literature, an 80% lower must be finished by you and only you. Not given or sold to anyone else as that is considered manufacturing. You can build a non serialized firearm yourself for yourself, quite strictly.

My 80%'s have nothing on them. I may engrave something under the pistol grip. Just a few numbers or a symbol, even a pet name or something.

False.



No grey area.

Manufacturing a firearm, in the sense of and 80% AR lower is cutting the FCG pocket and drilling the pin holes.  Once that is done, you have a 'firearm receiver', prior to that you have a paperweight.  There are no laws restricting the engraving, modifying or doing anything to a paperweight.

???
It's an 80%, there usually is no "previously engraved and registered number".

The bottom line is...

While you have apparently read a bit on finishing an 80% receiver, you have not read up on what "manufacturing" actually entails, and what can be done to a finished firearm, and by whom it can be done.

Prior to an object being a firearm, anything can be done and by anybody.  I can mail my '80%' to anybody in the US and have them engrave, paint, re-machine anything, provided they do not cut any part of the FCG pocket or any of the three holes.

The cutting of the FCG pocket and the three holes, must be done by you and you alone.

After you have done that, it is a firearm.  You can have anybody you want engrave ducks, or dogs or words and numbers on your firearm without any 'manufacturing license', provided it can be hand carried to the shop, if it needs to be shipped by a third party, then an FFL will be required, and they would want a S/N on it.

NOTE ON SERIAL NUMBERS: The BATFE as certain requirements on serial numbers, basically, they have to be unique to the model, at least .003" deep, be permanent in nature, and visible without disassembly. If your numbers do not follow these criteria, they are not considered serial numbers.  Since  homemade firearms are not required to have s/n, you can put 'idenifying marks' anywhere and however you choose, but these are not serial numbers.  If at some point in the future, you wish to transfer the firearm, a true serial number will probably make life easier. For lost or stolen things, an 'identifying mark' will probably suffice.

All of this can be be found by reading the ATF's voluminous notes on the subject.

https://www.atf.gov/firearms/qa/license-needed-engage-business-engraving-customizing-refinishing-or-repairing-firearms

They say a license is needed just not a manufacturers license. Reviewed in 2015.

Any person who engages in an activity or process that primarily adds to or changes a firearm's appearance, by camouflaging a firearm by painting, dipping, or applying tape, or by engraving the external surface of a firearm, does not need to be licensed as a manufacturer under the Gun Control Act. Any person who is licensed as a dealer/gunsmith, and who camouflages or engraves firearms as described in this ruling does not need to be licensed as a manufacturer under the Gun Control Act. Any person who is engaged in the business of camouflaging or engraving firearms as described in this ruling must be licensed as a dealer, which includes a gunsmith, under the Gun Control Act.

The key word(s) there are "engage in the business"...

Otherwise, taking a can of Krylon to a friend's stock would require a license.

A quote from Title 27 CFR 478.11 - Meaning of terms. (relevant parts bold)



A trophy shop can engrave your stuff without a license, unless engraving guns is their principle means of income.

As far as the ATF is concerned an 80% lower is NOT a firearm. They couldn't care less about who does any engraving or anything else until the actual finishing process has begun.

You may not build a firearm with the intent of selling it, but you still can transfer it to another, however at that point it will need to have a serial number.

We really need an 80% forum.  Or at the least a tacked thread with laws and facts.  This like every other thread questioning 80% legalities is full of misinformation.

Some local/state laws require it even if Federal statutes don't. Shameful I know, but it is what it is.

This issue can be resolved very easy BUY A HEAVIER HAMMER!!  The going back & forth over who can , cannot or maybe do something, while informative. IS not addressing the question the OP had.

His real problem is lack of the proper tool for the Job. Nothing more. I've said it in a few other threads. IF one is going to do anything firearm , automotive, fabrication related. HAVE THE CORRECT TOOLS ON HAND.  
Don't duracote something, THEN ASK what's the best way to cure it.


As for getting the lettering / stamping looking 1/2 way decent. figure out the thickness of the stamp. That's your guideline. NOW take some tape (painters, masking, etc) Lay it along either side (top & bottom) of that measurement. Now use a pencil to mark (vertically) same thickness the length of said info you want to put for a serial #.  This is your template.  Now use the stamps to do the job.

ANOTHER WAY to put info on metal is use one of these.
http://www.harborfreight.com/spring-loaded-center-punch-621.html

Use some painters tape with the serial # printed on it. Use this spring loaded punch to "stipple" the info on your lower. I did this method on one of my Form 1 suppressors.  Looks  something like the info on a com-bloc AK

YMMV.

I jumbled thoughts together in my last post.
My previous post assumed that prior to having a shop engrave it, the lower had been finished into being functional. But yes, while still an 80% they can put crap on there all day. What I meant by " a previously engraved number", is if you engraved your own in a manner that is obviously different from the REAL serial numbers, then if seen by a cop, they would be able to see YOU engraved your own, and did NOT alter a real federal serial number on a manufactured lower. I should have plainly said, from the cops perspective, your 80% lower number or symbol would not look like an altered federal serial number " previously placed on a manufactured lower". My bad there.
As far as manufacturing goes, I meant if you already finished the lower, a real federal serial number could not be placed on it by a shop as that would be manufacturing as a result of them serializing it. I'm pretty sure that's right. And once finished I thought only YOU could work on it.

Manufacturing and an FFL being unable to work with a finished 80% are separate issues I poorly separated in my last post.

Though once finished into functional, I thought that no one but yourself can alter it or work on it at all. Try taking your finished 80% lower to a gunsmith with an FFL to get some kind of work done. They can't. I'm pretty sure. Unless there's a detail I'm missing. I took my new barrel and new f marked fsb for drilling and pinning, I took my completed lower half and upper receiver in there with me, which has a finished 80% lower. They were confident in being legally unable to do anything with my lower. I didn't need them to, but that's what was said. And I've heard and read that from many other FFL holders and sources. I think that's because my rifle was being built. They can't do that with a finished 80% lower. But if I asked for something cosmetic like duracoat, maybe that's ok? After I finished the machining I don't think so. Wrong?

I jumbled thoughts together in my last post.
My previous post assumed that prior to having a shop engrave it, the lower had been finished into being functional. But yes, while still an 80% they can put crap on there all day. What I meant by " a previously engraved number", is if you engraved your own in a manner that is obviously different from the REAL serial numbers, then if seen by a cop, they would be able to see YOU engraved your own, and did NOT alter a real federal serial number on a manufactured lower. I should have plainly said, from the cops perspective, your 80% lower number or symbol would not look like an altered federal serial number " previously placed on a manufactured lower". My bad there.
As far as manufacturing goes, I meant if you already finished the lower, a real federal serial number could not be placed on it by a shop as that would be manufacturing as a result of them serializing it. I'm pretty sure that's right. And once finished I thought only YOU could work on it.

Manufacturing and an FFL being unable to work with a finished 80% are separate issues I poorly separated in my last post.

Though once finished into functional, I thought that no one but yourself can alter it or work on it at all. Try taking your finished 80% lower to a gunsmith with an FFL to get some kind of work done. They can't. I'm pretty sure. Unless there's a detail I'm missing. I took my new barrel and new f marked fsb for drilling and pinning, I took my completed lower half and upper receiver in there with me, which has a finished 80% lower. They were confident in being legally unable to do anything with my lower. I didn't need them to, but that's what was said. And I've heard and read that from many other FFL holders and sources. I think that's because my rifle was being built. They can't do that with a finished 80% lower. But if I asked for something cosmetic like duracoat, maybe that's ok? After I finished the machining I don't think so. Wrong?

Sorry, posted the same dang thing twice, and it was too long to click quote the first time...Uhhg. Unless I screwed that up too.

Sure they can.

A lot of firearms were made and sold without serial numbers prior to 1968, and gunsmiths can work on them.

Most people don't know, and don't care to find how all the rules.  There are plenty of non-serialized guns still in circulation. When they come into the shop you just mark "NSN" or "NONE" for the serial number in the bound book.

For your situation, one really simple solution is to stamp a serial number on an unobtrusive, but still visible place, like in between the front pivot lugs just below the pin, If it ain't pretty, who cares, as long as it is 1/6 inch high and .003 inches deep. . .

One you start machining an 80%, it's a firearm, same as a completely finished lower.  Anything you can have done to a store-bought finished lower, you can have done to your 80%.

Back to google:

Search this
"Your_City's_Name Gun Engraving"

I use to live in San Antonio and now live in Dallas. I know of places in both of those areas and Austin that will do this same day for $100 or less. The best one is in San Antonio and you can even watch him do it!

But you live in Texas and you do not need a serial number for your gun

San Antonio Engraving http://www.graylaser.com/

Thanks for the advise! I went down to harbor freight in Austin and picked up one of those. I tried it in the pistol grip tang just to see what it does and it works! Now I can just print up some dot martix font and label the lower to my heart's content.

I got a glock slide that has dot matrix number on the barrel/slide as well... so manufacturers use them too.

Best thing is, the thing just works without a hammer.

I stamp serials on the right side, behind the selector hole, with a cheap set of Harbor Freight stamps. Works great.

Do it before you mill out the lower and smack it manfully.

My only reason for marking them is to identify them in case of theft.

Is this you?


The stamps you have, plus bigger hammer is probably going to be the best way to do it.
If you do the dot matrix center punch thing, test it out on a piece of scrap aluminum because when you actually try to write stuff with it, I can't imagine that turning out not looking like shit.

The absolutely cheapest way is to "manfully" whack letter stamps on you UNCUT forging.  Uncut because there's lots of metal to absorb your manliness () and keep you from borking your forging.  For neatness sake you can trace the data you want on the forging and just keep the stamps lined up with the tracing.  Second whacks take a little more attention, but if you just get the stamp into the dent it made with the first whack and hold it firmly as the hammer hits it, it will work fine.

The neatest and quickest solution is to take the UNCUT 80% forging to a trophy shop and have them engrave what you want where you want it.

Engraving a serial number and/or maker information may be considered a "manufacturing" step.  Remember, ATF requires some substantial paperwork before allowing a mill that produces lowers for various brand names to do that work.  This is called a "marking variance."  Say JD Machine contracts with Joe's Gun Shop to make lowers marked "Joe's Gun Shop" and with Joe's serial number sequence.  ATF has to approve a variance for JD Machine marking those lowers with Joe's logo and "Joes Gun Shop, Anytown USA" instead of JD Machine, San Diego CA*.  How different is that from having YOUR data engraved on a lower?  So if you plan to have your 80% lower engraved professionally, have it done BEFORE you mill it.

*My first SBR lower is marked "SOG Armory, Houston TX" and was made by JD Machine for them.  JD Machine does this for a lot of "non-manufacturer" companies.

1. Use a laser or inkjet printer to print your serial number on adhesive-backed paper (shipping label or similar), using a 5x7 dot-matrix font:



2. Stick the label on your lower's magazine well.

3. Use a center punch to mark each "dot" location on the lower.

4. Use a small drill bit in a drill press to produce a deep indentation in each "dot" location (or drill completely through the side of the magazine well for extra awesomeness! )

5. Remove the label.

6. Open an ice-cold bottle of Victoria™, sit back, and admire your handiwork.