The first proof marks started appearing in 15th century France, and by the 17th century, European firearms guildsmen were heavily promoting their use - and lobbying their governments for laws requiring them - primarily to dissuade competition from non-guildsmen and scare potential purchasers away from un-proofed guns. But like many government regulations, their origins have more to do with self-interest than safety. In modern years, they truly do serve that purpose. Proof marks are stamps embedded in certain parts of a firearm following (and sometimes during, depending on the firearm type) its manufacturing to indicate that the firearm has been “proven” to be able to handle the specific type of ammunition for which it was designed. And even if you’re already familiar with proof marks, maybe this article can broaden your knowledge and teach you something new. If you’ve heard someone mention proof marks or date codes when discussing a SIG Sauer pistol, but weren’t quite sure what those were, then the goal of this article is to bring you up to speed.
