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+5 votes

***Note - I am not a lawyer. This is not legal advice. Check for yourself before making decisions regarding these laws***



It is legal to manufacture a firearm yourself in the U.S. so long as you do not sell it or transfer it in any way. The firearm may not be NFA restriction, etc. Assuming that the firearm you make is legal and is not transfered,


1. The Undetectable Firearms Act restricts 100% polymer firearms. There must be at least 3.7 oz of steel in the receiver / frame, and it cannot be removed (despite what Schumer thinks). This law was recently renewed for 10 years.

2. All other laws applicable to making firearms apply, the UFA is the only one that applies specifically to these types of weapons. If you are lucky enough to own a Sintering machine that does metal you can disregard the UFA since the whole gun will be metal.



1. California has laws against some types of weapons, such as revolving cylinder shotguns or 'assault weapons'. This includes banning all magazines over 10 rounds.

2. California has a 'zipgun' law that bans the creation of any weapon not designed by an FFL. This means that the Liberator would most likely be legal because DD has an FFL, while my design the Protector would be illegal because I am not an FFL. 

3. CA also has its own UFA, so even if the national one were to expire, CA would still have it.


Final note: Remember to check on all laws before making anything. Don't trust me alone. I do not hold responsibility if any of this information is incorrect.

kicked off in Laws by (390 points)

1 Remark

+2 votes

California has many very confusing laws but the main ones to be informed of when making or building your own guns is the Assault Weapons Ban, laws regarding magazines, and others.

Calguns has a flowchart for rifles that covers most questions http://www.calguns.net/caawid/flowchart.pdf California is also one of those states that have "assault pistol" and "assault shotgun" definitions, and quite some reading will be required if you wish to comply with all the various laws.

When it comes to magazines over 10 rounds in California it is NOT illegal to possess or use them, however it is illegal to import, manufacturer, give, sell, keep for sale, etc. It is not illegal to replace parts of currently owned magazines, including every single part. As of 1/1/2014 it is illegal to import "magazine rebuild kits" however separate parts are still legal to import it would seem.

Also in California there are various standards that differ from the federal standards, for instance if you have a folding or sliding stock, the overall length of your rifle is measured with the stock closed or folded. There are many cases in CA that have set precedents that are inconsistent with federal laws and standards.

The laws regarding "zip guns" in California are very vague and are questionable, this PDF should shed some light on the problems http://calgunlaws.com/wp-content/uploads/2014/03/3D-Printing-of-Firearms-Federal-and-Claifornia-Law.pdf

As for the Federal UFA, firearms minus the stockgrips, and magazine, must have an X-ray detection signature no less than that of a calibration sample containing 3.7 ounces of stainless steel. Fun Fact: 3.7 oz. is exactly half the metal in a standard Glock 17 Gen 1, and the original bill was passed with no current firearms being affected. Also the Military and CIA are exmept from the UFA.


Do not take my advice alone, if you intend to produce your own firearms, understand your local and federal laws

remarked by (310 points)

It is still unclear if making an original design not based on those created by FFL'd firearms manufactures is always concidered a zip gun in california.

D. California “Zip Guns” Law [1]
Under California law, a 3D-printed firearm also has the potential of meeting the definition of a “zip gun.” Generally, a “zip gun” is a “crude homemade pistol.” American Heritage Dictionary of English Language 2003 4ed. 2006. The restrictions, California Penal Code § 33600, and exceptions for “zip guns” are the same as those for “undetectable firearms.” See Cal. Penal Code §§ 17700-17745. A “zip gun” is defined as a weapon or device that meets all of the following criteria:

(a) It was not imported as a firearm by an importer licensed pursuant to Chapter 44 (commencing with Section 921) of Title 18 of the United States Code and the regulations issued pursuant thereto.

(b) It was not originally designed to be a firearm by a manufacturer licensed pursuant to Chapter 44 (commencing with Section 921) of Title 18 of the United States Code and the regulations issued pursuant thereto.

(c) No tax was paid on the weapon or device nor was an exemption from paying tax on that weapon or device granted under Section 4181 and Subchapters F (commencing with Section 4216) and G (commencing with Section 4221) of Chapter 32 of Title 26 of the United States Code, as amended, and the regulations issued pursuant thereto.

(d) It is made or altered to expel a projectile by the force of an explosion or other form of combustion.

From what I'm reading it sounds like the current interpretation of the law is that it doesn't have to be a zip gun, assuming you avoid AOW features like use a rifled barrel for pistols etc.

[1] http://calgunlaws.com/wp-content/uploads/2014/03/3D-Printing-of-Firearms-Federal-and-Claifornia-Law.pdf
[2] http://www.calguns.net/calgunforum/showpost.php?p=3526827