I am a keen hunter and have been a crossbow enthusiast for the past five years.
What's a Broadhead?
A crossbow broadhead is an arrowhead designed specifically for hunting.
If you are practising shooting you don't use broadheads, you would use field-tips. You only use broadheads when you want to hunt game.
What do I want from a good broadhead?
There are many different broadhead types out there, but they all try to achieve the same things:
A broadhead must be able to penetrate the skin of an animal and go as deep as possible, thus causing maximum damage.
Ideally an arrow will come out of the other side. Think about when you open a box of juice; if you cut a second whole the juice comes out far quicker thanks to the air being able to run through it.
This is the same with an animal. It sounds brutal, but ethically you want the animal to die as quickly as possible.
Broadheads are bigger and wider in design because they need blades in order to pierce an animal's skin. Unfortunately that leaves them more susceptible to influence by the wind.
To be as accurate as possible, broadhead manuacturers try and test various designs to reduce drag.
One of the advantages of mechanical broadheads (see below) is that they fly like field-tips, because the blades don't deploy until the moment of impact.
A wide wound channel achieves two things. Firstly, it's more likely you will nick a vital organ or artery to kill the animal. If this is not the case, a wide wound channel will nonetheless increase bleeding, cutting through more capillaries. This leads to the animal bleeding out quicker.
Often when hunting you will hit a target, but the target won't go down straight away, even running for hundreds of yards before finally not being able to continue.
If that happens it's easy to lose animals. The way to find them is by following the blood trail left by the wound. Some broadheads don't create much of a blood trail, making it difficult to find your kill. The bigger the blood trail, the better.
A Fixed Broadhead or a Mechanical Broadhead?
There are principally two types of broadhead, and many hybrid variations somewhere in between. The two types of broadhead are fixed-blade broadheads and mechanical broadheads.
A fixed-blade broadhead is a traditional broadhead, and what you'd expect to find on the head of an arrow if you have little experience of hunting.
Normally in some two or three-blade variation, they're favoured over mechanical broadheads for their reliability.
Mechanical broadheads are a newer design with the objective of increasing the aerodynamic efficiency over traditional broadheads.
The blades start hidden inside the bolt's shaft until deploying themselves upon impact, to cause maximum damage.
Having a small tip to the arrow not only reduces external influences on the arrow such as wind or rain, but also allows the arrow to be driven by its vanes.
Understanding your Broadhead's Features
Cutting diameter refers to the diameter of not the shaft, but the blades of the broadhead when fully deployed.
Fixed-blade broadheads typically have a smaller cutting diameter of anywhere from 1 inch to 1.5 inches. On mechanical broadheads you tend to find cutting diameters of upwards of 1.5 inches.
When hunting big game you can find cutting diameters for both designs increase, on mechanicals reaching upwards of 3-inch diameters.
A larger cutting diameter means a greater wound channel, and more likely a strong blood trail.
It may however reduce penetration.
Broadheads normally weigh around 100 to 150 grains. The larger grain weights are for hunting larger game, or for customizing your overall bolt weight to your liking.
You can control aspects such as bolt power, penetration and FOC by changing the weight of your broadhead.
There are two types of blade tips. There is a wider, blunter 'chisel-tip' which is designed for a heavy impact on big game. It will stop most animals in their tracks.
The alternative is a cut-on-contact tip which is designed to immediately slice open an animals skin and fat in order to penetrate and wreak havoc on an animals insides.
Number of Blades
Most broadheads have variations of one, two or three blades. My personal rule is, if I want more bone-splitting, deeper penetration then I'll go with a two blade. Three blades is better for increasing the wound channel.
The right broadhead for you depends entirely on the game that you are hunting and your needs as a hunter.
By following the above rules I'm sure you can test different options to find some combination which suits you perfectly.
Some people swear by fixed-blades for their reliability, however more and more people are switching to mechanicals for their obvious design improvements and results.