The typical firing pin is a small simple rod with a hardened, blunted/rounded tip that strikes and crushes the primer. The rounded end ensures the primer is indented rather than pierced, as would otherwise happen if the firing pin were sharply pointed. Most firing pins are connected to a return spring to pushes them back and out of contact with the primer, and often will have an integrated passive safety mechanism such as a catch that blocks them from moving forward unless the trigger is depressed, or a "transfer bar" (also trigger-actuated) that must be in place to allow the hammer to impact the firing pin. This integrated safety is in addition to any manually operated safety mechanisms that deactivate the trigger or hammer.