Easton 9mm Crossbow Bolts 20 in. Brass Insert Half Moon Nock 6 Pk Black. The 9mm Bolt has an inside diameter of 0.300" and will fit universal bolt components. Specifications for Easton 9mm Crossbow Bolts Brass: Manufacturer: Easton Color: Black Features of Easton 9mm Crossbow Bolts Brass: High-strength carbon construction Inserts are included with fletched bolt Shaft weight: 8.9 gpi BTV Vane: 10 grains 9mm Crossbow Insert: 61 grains Package Contents: Easton 9mm Crossbow Bolts Brass Easton 930074: 9mm Crossbow Bolts 20 in. Brass Insert Half Moon Nock 6 Pk Black