Preban AR-15 magazine identification

Here is a guide with photos on how to identify whether or not an AR-15 magazine is pre-ban.  Thanks to ARK for this great information.  ARK has inspected over 500 pre-ban magazines and all of the magazines that he has seen have confirmed what is included in this article.   However, please understand that we are not lawyers, law enforcement or industry experts so you are responsible for how you use this information and for verifying your own magazines.

ARK writes:

Method 1:
An external preban date stamp. I have only seen two versions of the preban date stamp that I can recall as of now and I have included a picture of these two versions below. This method of preban identification is a guarantee that the mags are preban and are the preferred type of mag to have, in my opinion.

Method 2:
An internal preban date stamp that can be found inside the bottom of the magazine. I have come across a few magazines that have been externally date stamped and internally date stamped and the external date stamp has matched that of the internal stamp. The magazine will usually be stamped on both sides internally with letters and numbers, such as “K4 87″ on one side and “04 87″ on the other, these date stamps refer to a magazine made in April 1987. The “K#” stamp can be stamped in the vertical or horizontal position and isn’t always stamped in the same direction as the “##” stamp. So a magazine might look like it say “K11 98″ when it really is a “K11 86″ stamp.

Method 3:
The third method to determine if a magazine is preban is the lack of any date stamp, internally and/or externally, and the lack of any Mil/LEO stamps.  If a magazine is absent of any stamps it is generally considered to be preban.  Please be careful and use your head with this method.  Obviously not all unmarked magazines are preban.