Law Research on Home Built firearms

Alex Osinski

This is by no means an all inclusive work on the laws surrounding firearms that you build in your workshop, but it should provide some useful and relevant information and legal references for those with common questions about the legality of making guns or making guns from 80% receivers.   I have included direct copy of legal text, links to government websites and published professional legal opinion on these issues.   If you are aware of any changes in these laws or the overall situation, you may contact me and I will research it and publish those changes as they become relevant.    I will not however, submit to interrogation by email from people who seem to have convinced themselves of positions contrary to what I have published here as law and fact.   If you have referenced information about specific state laws that I have not referenced here, especially for those of other states that I did not research at all, I will be glad to incorporate it into this page.   

Just a quick note for the benefit of those who still have questions about the legality of home built firearms.  I have included links to a page on another site which had links to the official BATF site with information on the legal issues surrounding home built and prototype firearms built by unlicensed manufacturers.  I have also answered numerous questions regarding this in person and by email.  CLICK HERE FOR  A DIRECT LINK TO THE BATF FAQ ON THE LEGALITY OF BUILDING YOUR OWN FIREARMS. which is the official BATF website dealing with these issues.  

A7) Does the GCA prohibit anyone from making a handgun, shotgun or rifle? [Back]
With certain exceptions a firearm may be made by a nonlicensee provided it is not for sale and the maker is not prohibited from possessing firearms.  However, a person is prohibited from making a semiautomatic assault weapon or assembling a nonsporting semiautomatic rifle or nonsporting shotgun from imported parts. In addition, the making of an NFA firearm requires a tax payment and approval by ATF. An application to make a machinegun will not be approved unless documentation is submitted showing that the firearm is being made for a federal or state agency. [18 U. S. C. 922( o), (r), (v), and 923, 27 CFR 178.39, 178.40, 178.41 and 179.105]
Translation:  It IS legal for an individual build a post ban compliant firearm from any combination of parts that could legally be assembled into a legal commercially available firearm by a manufacturer or importer.   This includes designs based on the AR15, AK, FAL, 1911 and others that are not protected by patent rights.   

Several states like California and Oregon have specific laws against the manufacture of your own firearms.   I have been researching both California and Oregon laws in this regard because they have been most important to me (having been a resident of both states).   Here are relevant references to the laws that I see are most relevant to the issue.  

The Oregon law reference is ORS 166.410 you can view the official state government text at

166.410 Manufacture, importation or sale of firearms.  Any person who manufactures or causes to be manufactured within this state, or who imports into this state, or offers, exposes for sale, or sells or transfers a handgun,  short barreled rifle, short barreled shotgun, firearm silencer or machinegun, otherwise than in accordance with ORS 166.250, to 166.270, 166.280, 166.291, 166.292 and 166.425 to 166.470, shall be guilty of a Class B felony.   

OK, if someone cares to read the statute minus "all them thar references and numbers and mumbo jumbo" cuts to the chase reads the first few words and the last few words to mean it is a Any person who manufactures....shall be guilty of a class B felony.  Such a person is committing a mistake by not completely applying the fairly big host of exceptions under the other statutes that to allow for the transfer or ownership of a firearm.   Federal law prohibits the transfer of a handgun to a person under 21 years of age except under certain circumstances.   Oregon statute 166.470 (a) under prohibitions states "is under 18 years of age" but under 166.470 subsection 3 this subsection does not prohibit:  The parent or guardian, or another person with the consent of the parent or guardian, of a minor from transferring the firearm to a minor to a firearm other than a handgun.   Thus a parent may not transfer a handgun to a person under age 18, but there is no apparent state prohibition against doing this with a person under age 21 but over age 18.   It is also my interpretation that a parent may not be authorized to permit a minor to manufacture a handgun or manufacture a handgun and transfer it to a minor, whether or not the person is a parent or guardian or has the consent of a parent or guardian.   One point, however is that a person who is under 21 may not be granted a concealed handgun license.  

Well, lets look at "them thar references" under the 'otherwise than in accordance with' section.   ORS 166.250, to 166.270, 166.280, 166.291, 166.292 and 166.425 to 166.470 all deal with lawful possession of firearms and the people and places persons would or would not be allowed to possess them.   What ORS166.410 does is tie the manufacture of a firearm in with the rest of the Oregon gun laws related to obtaining or possessing a firearm.  It changes nothing but does make it a felony for certain prohibited persons and situations to manufacture a firearm where it might only be a misdemeanor under the other statutes.   Example, ORS 166.425 Unlawful purchase of a firearm (2) "Unlawfully purchasing a firearm is a Class A misdemeanor".   Manufacturing the gun by a prohibited person then is not a smart way to avoid a violation of ORS 166.425 since what would have just been a Class A misdemeanor, then is a Class B felony under ORS 166.410.  This is not be confused with someone in possession of the firearm they made themselves prior to becoming a prohibited person.  

What is omitted in ORS 166.410 is any reference to ORS 166.412.   The reason for this is that the manufacture of your own firearm is a private activity and falls under the same protections of a private firearms acquisition and thus not regulated by the section entitled 166.412 Definitions; firearms transaction record; criminal record check.   Thus you are under no obligation to disclose the number or type of firearms you have manufactured for personal use, their location or disposition or even maintain records of the dates or places of manufacture provided you neither sell nor give the guns to another person.  

Is a serial number required?  ORS 166.450 Obliteration or change of identification number on firearms.  Gives us the detail on this.   "Any person who intentionally alters, removes, or obliterates the identification number of any firearm for an unlawful purpose, shall be punished upon conviction by imprisonment in the custody of the Department of Corrections for not more than five year.  Possession of any such firearm is presumptive evidence that the possessor has altered, removed or obliterated the identification number."   This statute specifically deals with pre-existing serial numbers on a firearm.   It does not deal with the absence of a serial number in the first place.   Thus, possession of a firearm without a serial number is not a crime if the firearm did not have a serial number in the first place.   It is a crime, however, for licensed manufacturers to sell such guns without serial numbers (federal law eg GCA 1968).  

A big gray area is the sale or trade of a personally built firearm.   Such activity is not specifically dealt with in Oregon law, and is only addressed in the federal restriction against the manufacture of the gun with the intent to sell.   Example, you built the gun in 1989 and then privately trade it to a person to who is lawfully entitled to own a firearm of that type in 2003.   There is not a specific statute in Oregon law to address this as illegal, and under federal law, there is the logic involved with the "intent" clause of existing statute.   Thus charges leveled against a person would have to include elements of the intent to do business building and selling firearms while said person is a non licensed manufacturer.   

California Pena Code Generally deals with these issues in a similar manner, ref CPC 12090 thru 12094 Obliteration of Identification Marks,  CPC 12085 thru 12086 Firearms Manufacturer Licensing.   One very significant difference in California pertains to the transfer of any handgun not listed on the DOJ approved handgun list, IE handguns that have or have not passed the drop test and of course the assault weapon laws in California.   

There are some interesting exemptions in the California law.  12085. (a) Commencing July 1, 1999, no person, firm, or corporation licensed to manufacture firearms pursuant to Chapter 44 (commencing with Section 921) of Title 18 of the United States Code may manufacture firearms within this state unless licensed pursuant to Section 12086. ..(b) Subdivision (a) does not apply to a person licensed to manufacture firearms pursuant to Chapter 44 (commencing with Section 921) of Title 18 of the United States Code who manufactures fewer than 100 firearms in a calendar year within this state.

The boogeyman under most of the California regulations is the definition of "zip gun" under CPC 12020

10) As used in this section, a "zip gun" means any weapon or device which 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. (note: you can view it here

(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.  (view here at

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

The part to examine here is under section C.   While you do not pay a tax on the weapon or device under federal law due to not being a licensed manufacturer.  CPC 12020 10 (c) recognizes the federal regulation in regard to the legality of firearms built lawfully under current federal regulations and deferring to amendments under title 18 chapter 44 of the United states code.   If we consider the term manufacturer, as it is stated in USC 18 chapter 44 , 921, a manufacturer is"(10) The term ''manufacturer'' means any person engaged in the business of manufacturing firearms or ammunition for purposes of sale or distribution; and the term ''licensed manufacturer'' means any such person licensed under the provisions of this chapter.   First, we have to consider who is exempt from the tax under 4181  ATF has held that the tax is paid when the item enters commerce.  If you manufacture the gun yourself and are not a licensed manufacturer, there is the implied exemption from the excise tax as is common ATF practice.   Part of this is the confusion in determining the trade value of an item that is not intended to enter into commerce and thus under section 4216, a price cannot be determined if the item is not offered for sale.   Reference 4216 (B)1(a) "the item is sold at retail".   The rest of 4216 relates to terms and conditions at which a price is determined for basing the excise tax.   All of these terms and conditions are hinged on the gun entering commerce.  The traditional tax being 10% to 11% of the wholesale trade price of the item that the manufacturer charges to a buyer which is usually the dealer or distributor.   Note that this is not fixed as a percentage of a manufacturer's suggested retail price.   Section 4221 is referenced in the text of the law and deals specifically to tax exempt sales and we can see the logic in how this would apply to a firearm that is not normally taxed by BATF.   

A gray area falls under "originally designed by".   If your home made gun was not designed by a licensed manufacturer, it may fall under the definition of Zip gun under California law.   If it is a copy of a gun originally designed by a licensed manufacturer,  then it is not a zip gun.   One gray area of argument would be "who originally designed it" and of course if the design originated in the US, since manufacturers outside the US may not be licensed to manufacture in the US.   Thus, your home built copy of a Colt 1911A1 that was completed from an 80% finished frame would be "a gun originally designed by a licensed manufacture  under Title 921(10) but a copy of a Makarov that has not been designed by or patented from a US licensed manufacturer might be a design which could fall under the provision of the California Zip gun definition.   This will limit which designs can be made by the hobby gunsmith in California, but note that many designs for "improvised" guns originally came from licensed manufacturers like SWD/Cobray, Bill Holmes, Armalite, and many manufacturers of AR15 variants.   I have yet to come up with a criteria for determining who designed the gun as defined by DOJ or ATF, but I see no apparent reference to a requirement for it to have been patented or even regularly manufactured.   IE, it appears in my opinion, that a variation of a basic firearm design is still allowed and you are not specifically required to follow the original design in every detail.  

Another dangerous interpretation of the California Zip gun definition is that it may apply to certain percussion and black powder guns.   Note that CPC 1020 10 (d)  It is made or altered to expel a projectile by the force of an explosion or other form of combustion.  This is not limited to "fixed ammunition" as is stated in other laws that would exempt black powder guns from other regulation.   It also appears to be the primary language on which California DOJ hinges its position in claiming that "spud guns" or potato guns" are illegal in California.   Thus designing a gun to fire from the combustion of some volatile substance other than gunpowder is not a legally valid way around the statute.   

In short, building your own firearm in California is probably not going to get you in trouble with federal guidelines as long as that same gun, or design would be legal federally and you are authorized to own that gun (age limits immigration status ect)  What is not entirely clear is how the authorities would interpret the state laws against "zip guns" but there is a strong indication that if the gun is otherwise compliant with California law and the person is otherwise authorized to possess the gun, it will be legal as long as it does not meet ALL of the criteria spelled out in the zip gun statute and those criteria leave a bit up to interpretation about designs,  manufacturer tax status,   codes a manufacture would be exempted under tax code, and what constitutes the criteria of being a "manufacturer" as opposed to a person who manufactures something that is not for commerce.   

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