Ruger Mark IV Standard

THE PAGE MARKETS TWO MODELS AND EMBEDS A SPEC OBJECT FOR ONE. Model 40105 is the same Standard with a 6 in barrel, shown on the same page at the same $579 MSRP, and Ruger publishes no specification object for it, so its dimensions are not available here and it is a separate listing under the base-model rule. The extractor now warns when a page displays catalogue numbers it has no spec object for, because "1 catalogue entry" otherwise reads as "Ruger lists one model here" — which is false, and which would scope a record to the wrong catalogue silently. The wider Mark IV family — Target, Hunter, Competition, Tactical, the 22/45 and 22/45 Lite — are separate product keys entirely. THE SLIDE FINISH IS DELIBERATELY UNSET AND THE REASON IS RUGER'S OWN DATA MODEL. Ruger's JSON carries BOTH a firearm-level `finish` and a slide-specific `slide_finish`; here `finish` is "Blued" and `slide_finish` is EMPTY. Recording Blued as a slide finish would fill a slide-specific field from a firearm-level one while the maker's own slide field sits blank — and this pistol has an internal cylindrical bolt rather than a conventional slide, which the page describes. Contrast the RXM, whose `slide_finish` Ruger does populate ("Black FNC Nitride") and whose record sets the field on that basis: the two Ruger records differ because Ruger's data differs, not because the rule changed. Year introduced is Ruger's own `introDate` of 2017-09-05, the same field the RXM record uses, so it is footnoted to the product page rather than to a launch release. Ignition, trigger action and operating system are all unset, as on the RXM: Ruger's `action` field reads "Rimfire", which is a cartridge class rather than any of the three axes, and the page never describes the mechanism. NOTE ONE SUBSTRING TRAP THIS PAGE SETS: the word "hammer" appears once, in "cold hammer-forged barrel" — a manufacturing process, not an ignition mechanism, and not a citation for anything. Warranty is unrecorded, following the RXM: Ruger's customer-service pages carry no warranty statement, and this page contains no occurrence of the word. Height and weight carry basis notes because Ruger does not say whether either includes a magazine. Ruger publishes imperial only, so every metric value here is converted and flagged. Also published and unrecorded for want of a schema field: a 1:16 twist with 6 grooves, an alloy steel construction with an aluminium grip frame, checkered synthetic grips, a tapered barrel, an internal lock, UPC 7-36676-40104-8, and the $579.00 MSRP. Ruger's data also carries an explicit `discontinued` flag, which reads 0 for this model — the one maker here that states production status outright, though the directory records no such field.