Smith & Wesson K X Frame Model 66-8 460 500 Extractor Rod Cap New Style Two-Piece Barrel 294200000 J539 The mainspring is the powerplant

The mainspring is the powerplant of the fire control system — it provides the force that drives the hammer forward to strike the firing pin and ignite the primer

and durability

Model 640 -

economical ammunition

This complete assembly includes the hammer and stirrup

Smith & Wesson K X Frame Model 66-8 460 500 Extractor Rod Cap New Style Two-Piece Barrel 294200000 J539 The mainspring is the powerplantFactory OEM Extractor Rod Cap for Smith & Wesson K & X Frame Revolvers This listing is for the extractor rod cap only. Genuine Smith & Wesson OEM extractor rod cap for new style two piece barrel revolvers. Threads onto the extractor rod and secures it to the barrel underlug, preventing the rod from backing out during firing and ensuring proper ejection when the cylinder is opened. Compatible Models (New Style Two Piece Barrel Only): K Frame Model 66 8