{"product_id":"sw-k-frame-model-66-cylinder-yoke-assembly-357-magnum-stainless-6678b","title":"Smith \u0026 Wesson K Frame Model 66 Cylinder \u0026 Yoke Assembly .357 Magnum Stainless - 6678B","description":"\u003ch2\u003eSmith \u0026amp; Wesson K Frame Model 66 Cylinder \u0026amp; Yoke Assembly – .357 Magnum, Stainless\u003c\/h2\u003e\u003cp\u003eThis factory original \u003cstrong\u003eSmith \u0026amp; Wesson K Frame Cylinder \u0026amp; Yoke Assembly\u003c\/strong\u003e is a complete stainless steel 6-shot cylinder and yoke unit for the Model 66 Combat Magnum revolver. The non-recessed cylinder design is correct for old-style Model 66 revolvers. The yoke aligns the cylinder with the frame and barrel, while the cylinder houses the six chambers — together they are one of the most critical assemblies in the revolver, directly affecting timing, alignment, and safe operation.\u003c\/p\u003e\u003ch3\u003ePart Details\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 6678B\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\u003eModel:\u003c\/strong\u003e 66 Combat Magnum\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCaliber:\u003c\/strong\u003e .357 Magnum (also accepts .38 Special)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Stainless Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCapacity:\u003c\/strong\u003e 6 rounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder Design:\u003c\/strong\u003e Non-Recessed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStyle:\u003c\/strong\u003e Old Style\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBarrel Compatibility:\u003c\/strong\u003e 3\" and longer barrels only\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e Used – Factory Original, Good Functional Condition\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\u003eBarrel\u003c\/th\u003e\n\u003cth\u003eCompatible\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e66 (old style, 3\"+ barrel)\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003e3\", 4\", 6\"\u003c\/td\u003e\n\u003ctd\u003e✓ Yes – Direct Fit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e66-1 through 66-4\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003e3\"+ barrel\u003c\/td\u003e\n\u003ctd\u003e✓ Verify – Check non-recessed design\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e66 (2.5\" barrel)\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003e2.5\"\u003c\/td\u003e\n\u003ctd\u003e✗ Not Compatible – Different cylinder fit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e19 (blued)\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003eVarious\u003c\/td\u003e\n\u003ctd\u003e✗ Verify – Different finish, same frame\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e65 (.357 Magnum)\u003c\/td\u003e\n\u003ctd\u003e.357 Magnum\u003c\/td\u003e\n\u003ctd\u003eVarious\u003c\/td\u003e\n\u003ctd\u003e✗ Verify – Different model configuration\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eK Frame .38 Special models\u003c\/td\u003e\n\u003ctd\u003e.38 Special\u003c\/td\u003e\n\u003ctd\u003eVarious\u003c\/td\u003e\n\u003ctd\u003e✗ Not Compatible – Caliber-specific cylinder\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eL, N, J Frame models\u003c\/td\u003e\n\u003ctd\u003eVarious\u003c\/td\u003e\n\u003ctd\u003eVarious\u003c\/td\u003e\n\u003ctd\u003e✗ Not Compatible – Frame-specific\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003e\u003cem\u003e⚠️ Cylinders are \u003cstrong\u003ecaliber-specific and frame-specific\u003c\/strong\u003e. This cylinder fits \u003cstrong\u003e3-inch and longer barrels only\u003c\/strong\u003e on old-style K Frame Model 66 revolvers. Verify your exact model, generation, and barrel length before ordering. Professional gunsmith installation and timing verification is required.\u003c\/em\u003e\u003c\/p\u003e\u003ch3\u003eInstallation Note\u003c\/h3\u003e\u003cp\u003eCylinder and yoke replacement requires full timing verification by a qualified gunsmith. Improper installation can result in dangerous cylinder misalignment. Do not attempt installation without proper tools and gunsmithing knowledge.\u003c\/p\u003e","brand":"Smith \u0026 Wesson","offers":[{"title":"Default Title","offer_id":41217409613882,"sku":"6678B","price":129.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1423\/2020\/files\/DSC03483.jpg?v=1769702393","url":"https:\/\/usagunsandgear.com\/products\/sw-k-frame-model-66-cylinder-yoke-assembly-357-magnum-stainless-6678b","provider":"USA Guns And Gear","version":"1.0","type":"link"}