If you’re looking to increase penetration on your crossbow hunting bolts, use Allen® 40 Grain Brass Crossbow Bolt Inserts. Ideal for increasing the FOC (Front of Center) balance on your hunting bolts, these 40 grain inserts are easy to install and will also improve your accuracy and decrease the noise of your crossbow firing. Hit hard and accurately and install Allen® 40 Grain Brass Crossbow Bolt Inserts on your bolts today.