{"product_id":"sw-k-frame-hammer-block-old-style-10120d","title":"Smith \u0026 Wesson K Frame Hammer Block Old Style - 10120D","description":"\u003ch2\u003eSmith \u0026amp; Wesson K Frame Hammer Block – Old Style\u003c\/h2\u003e\u003cp\u003eThis factory original \u003cstrong\u003eSmith \u0026amp; Wesson K Frame Hammer Block\u003c\/strong\u003e (also called the safety block) is a critical passive drop safety component that sits between the hammer and firing pin. When the trigger is not fully pulled, the hammer block prevents the hammer from contacting the firing pin — even if the revolver is dropped or the hammer is struck. Only when the trigger is fully depressed does the block lower, allowing the hammer to fire the cartridge. A missing or damaged hammer block eliminates this drop safety protection and must be replaced immediately.\u003c\/p\u003e\u003ch3\u003ePart Details\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 10120D\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Smith \u0026amp; Wesson\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFrame:\u003c\/strong\u003e K Frame (Medium Frame)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStyle:\u003c\/strong\u003e Old Style\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFunction:\u003c\/strong\u003e Passive Drop Safety \/ Hammer Block\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e Used – Factory Original, Functional\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eModel Compatibility\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eModel\u003c\/th\u003e\n\u003cth\u003eCaliber\u003c\/th\u003e\n\u003cth\u003eType\u003c\/th\u003e\n\u003cth\u003eCompatible\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e10, 10-10, 12\u003c\/td\u003e\n\u003ctd\u003e.38 Special\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e13\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e14, 15\u003c\/td\u003e\n\u003ctd\u003e.38 Special\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e16\u003c\/td\u003e\n\u003ctd\u003e.32 Long\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e17, K22\u003c\/td\u003e\n\u003ctd\u003e.22 LR\u003c\/td\u003e\n\u003ctd\u003eRimfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e18\u003c\/td\u003e\n\u003ctd\u003e.22 LR\u003c\/td\u003e\n\u003ctd\u003eRimfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e19\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e48\u003c\/td\u003e\n\u003ctd\u003e.22 Magnum\u003c\/td\u003e\n\u003ctd\u003eRimfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e64\u003c\/td\u003e\n\u003ctd\u003e.38 Special\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e65\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e66\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e67\u003c\/td\u003e\n\u003ctd\u003e.38 Special\u003c\/td\u003e\n\u003ctd\u003eCenterfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e617\u003c\/td\u003e\n\u003ctd\u003e.22 LR\u003c\/td\u003e\n\u003ctd\u003eRimfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e648\u003c\/td\u003e\n\u003ctd\u003e.22 Magnum\u003c\/td\u003e\n\u003ctd\u003eRimfire\u003c\/td\u003e\n\u003ctd\u003e✓ Yes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eL Frame models\u003c\/td\u003e\n\u003ctd\u003eVarious\u003c\/td\u003e\n\u003ctd\u003eVarious\u003c\/td\u003e\n\u003ctd\u003e✗ Not Compatible – Different hammer block\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003e\u003cem\u003e⚠️ This is the \u003cstrong\u003eold style\u003c\/strong\u003e K Frame hammer block. The hammer block is interchangeable across centerfire and rimfire K Frame models — not caliber-specific. This is a \u003cstrong\u003esafety-critical component\u003c\/strong\u003e — professional installation and full drop safety function testing by a qualified gunsmith is required before returning the firearm to service.\u003c\/em\u003e\u003c\/p\u003e\u003ch3\u003eInstallation Note\u003c\/h3\u003e\u003cp\u003eHammer block replacement requires side plate removal and action disassembly. Professional gunsmith installation is strongly recommended. Always perform a complete drop safety function test after installation.\u003c\/p\u003e","brand":"Smith \u0026 Wesson","offers":[{"title":"Default Title","offer_id":41238146187322,"sku":"10120D","price":5.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1423\/2020\/files\/s-l960_30_61319ac8-d56c-49ee-836c-b9dee8b67efc.webp?v=1770738477","url":"https:\/\/usagunsandgear.com\/products\/sw-k-frame-hammer-block-old-style-10120d","provider":"USA Guns And Gear","version":"1.0","type":"link"}