Lightweight crossbow bolts weigh-in between 350 to 399 grains, standard weight crossbow bolts range from 400 to 459 grains, and heavyweight crossbow bolts weigh-in at a hefty 460 grains and above. These bolt weights include the weight of a standard 100-grain field point in addition to the weight of the finished bolt itself. In other words, when we say the overall weight of a crossbow bolt is 400 grains, what we actually mean is that the finished bolt without the point weighs 300 grains and then you add the 100-grains from the field point to arrive at the overall weight of 400 grains.
First, to understand why there are different crossbow bolt weights, let’s talk about your hunting crossbow itself. Your crossbow transfers the energy stored in the bow assembly to your crossbow bolt through the string and accelerates it down the flight rail when you take a shot. Generally speaking, your hunting crossbow applies a consistent amount of force each time you shoot it. Increasing or decreasing your crossbow bolt weight, then, increases or decreases the speed at which the bolt travels. A lighter crossbow bolt is easier to move from a position at rest, so your hunting crossbow will shoot a lighter bolt faster than it will a heavier one. Conversely, your hunting crossbow will shoot a heavier bolt more slowly as compared to a lighter one.
For you to decide which weight is best for you to shoot, you must consider the scenario in which you are shooting. If you use your crossbow for competitive shooting, like 3D archery, you should choose a lighter bolt that travels faster. The faster a crossbow bolt travels, the “flatter” the trajectory it has as it is flying to your target. This means if you misjudge the distance to your target, a lightweight, flatter shooting bolt will drop less fast and you will miss your mark by a smaller margin than if you had used a heavier bolt. Archers often refer to lightweight crossbow bolts as being “more forgiving” for this reason.
If you are using your crossbow for hunting purposes, you should consider shooting a standard weight or heavyweight crossbow bolt. Despite the fact that these bolts will shoot more slowly, they carry a greater amount of kinetic energy, or penetration power, as compared to a lightweight bolt. Since maximizing penetration and cutting damage with your crossbow broadhead significantly increases your chances of harvesting an animal, you should shoot a crossbow bolt that has the greatest amount of kinetic energy while still shooting as fast and accurately as possible. Standard weight and heavyweight crossbow bolts also make your crossbow quieter, since more energy is required to accelerate a heavier bolt, leaving less energy to be dissipated from the crossbow as vibration or “game spooking” noise. Since there is less energy left over, shooting these arrows also means there’s less wear and tear on your hunting crossbow.