What prevents tourists visiting the U.S. from buying firearms?
<p>Imagine an ordinary foreigner, arrived with a simple tourist visa into the US.</p>

<p>In the U.S., there is no personal identification document. Most of the U.S. people doesn't have a passport.</p>

<p>What prevents a simple tourist to go into a weapon shop and buy a rifle?</p>

<p><a href="https://www.law.cornell.edu/uscode/text/18/922" rel="noreferrer">18 USC 922(g)</a> says that it is illegal for various persons</p>

<blockquote>
  <p>to ship or transport in interstate or foreign commerce, or possess in
  or affecting commerce, any firearm or ammunition; or to receive any
  firearm or ammunition which has been shipped or transported in
  interstate or foreign commerce.</p>
</blockquote>

<p>(5) refers to "being an alien", specifically one who </p>

<blockquote>
  <p>has been admitted to the United States under a nonimmigrant visa (as
  that term is defined in section 101(a)(26) of the Immigration and
  Nationality Act (8 U.S.C. 1101(a)(26)))</p>
</blockquote>

<p>with an exception </p>

<blockquote>
  <p>as provided in subsection (y)(2),</p>
</blockquote>

<p>The (y)(2) exceptions covers foreign officials and law enforcement (not a typical tourist), and one who is</p>

<blockquote>
  <p>(A) admitted to the United States for lawful hunting or sporting
  purposes or is in possession of a hunting license or permit lawfully
  issued in the United States;</p>
</blockquote>

<p>which pretty much covers simple tourists, if not typical tourists.</p>

<blockquote>
  <p>In the U.S., there is no personal identification document.</p>
</blockquote>

<p>That's not really true.  There is no standard personal identification document issued by the <em>national</em> government (if you don't count passports), but <em>state</em> governments do issue such documents.  The most common is a state-issued driver license, and people who do not drive can be issued a "non-driver ID" that is otherwise similar. Practically every US citizen or resident has one of these documents, and in practice they are used in a similar way to a national ID card.  (You could do an image search to see what they look like.)</p>

<p>In fact, there is an identification requirement for buying firearms; see 
<a href="https://www.atf.gov/firearms/qa/what-form-identification-must-licensee-obtain-transferee-firearm" rel="nofollow noreferrer">https://www.atf.gov/firearms/qa/what-form-identification-must-licensee-obtain-transferee-firearm</a>.  A state driver license or non-driver ID would be sufficient for this purpose, and that's what most people would use.</p>

<p>The link mentions that a foreign passport would be acceptable identification; but that doesn't mean a foreign tourist could actually buy a gun.  The <a href="https://law.stackexchange.com/a/24027/576">answer by user6726</a> cites the relevant law that restricts nonimmigrant aliens from firearm purchases.  </p>

united-states weapons