Tactical Aluminum Bolt Knob 5/16" x 24, Ruger Precision, Black Grenade Tactical Aluminum Bolt Knob 5/16" x 24, Ruger Precision Aluminum replacement Bolt Knob for the Ruger Precision or any with 5/16"x24 thread Unique Spiral Cut Style design. Highest quality, Lightweight, extremely durable, tumbled finish Made in the USA.