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.
