On October 11, 2018, four ceremonial M17s built by Sig Sauer's Custom Shop were presented to
The Old Guard for use by the Sentinels who guard the
Tomb of the Unknown Soldier at
Arlington National Cemetery. Each of the four pistols bears a specific name and theme engraved on the pistol's
dust cover: Silence, Respect, Dignity, and Perseverance. "Silence" and "Respect" are highly polished pistols with brown wood handgrips, which are used for daylight hours, while "Dignity" and "Perseverance" are matte black pistols with black wood handgrips for night duty and bouts of inclement weather. All four guns were made with an aluminum frame rather than the polymer plastic of the standard M17, while the controls are the standard matte black. The rear slide cocking serrations of the regular M17 are replaced with "XXI", a reference to the twenty-one steps the guards take on their patrol in front of the Tomb, as well as the
21-gun salute. The sight plates were laser-engraved with three Greek figures, Peace, Victory, and Valor, based on a digitized image of the figures as carved into the Tomb. Various materials of significance were incorporated into the pistols; the wooden grips on the daytime pistols were crafted from deck planks originally fitted on the
USS Olympia, the ship which carried the first Unknown Soldier to the United States in 1921, while the front sight posts on all four pistols feature glass vials holding marble dust that was taken when the "
Vietnam" crypt had its inscription changed to "Honoring and Keeping Faith with America's Missing Servicemen 1958 – 1975".
Serial numbers The pistols are serialized with a unique set of serial numbers that incorporate items of significance to the Old Guard: "LS" represents line six of the Sentinels' Creed, "My standard will remain perfection"; "02JUL37" to signify the first 24-hour guard posted at the Tomb of the Unknown on July 3, 1937; and "21" to signify the 21 steps it takes the Tomb Sentinels to walk by the Tomb of the Unknown and the military honor of a 21 Gun Salute.
Magazines Tomb Sentinels carry the pistol with the 21-round magazine inserted. The magazines are customized, and feature an aluminum base plate engraved with the names of the Greek figures featured on the Tomb of the Unknown – Peace, Victory, and Valor – and include a name plate on the bottom of the magazine engraved with the Tomb Sentinel badge number. == Commercial variants ==