Broadhead Talk: Choosing the Right Cutting Diameter

A week after new broadheads were unveiled at the ATA show in Nashville, it’s clear there’s diverse opinions about what broadheads are the best. We saw mechanical broadheads that looked like Swiss Army Knives and fixed-blade broadheads with spiral-shaped blades. There were Broadheads with cutting diameters in from 1” to 3”. The fullness of the broadhead market is great, but with such an array of options, educating consumers about cutting diameter becomes important.

Wasp Archery sells broadheads that cut big holes, like the Z-Force with a 1-5/8” cutting diameter and the Jak-Hammer with a 1-3/4” cutting diameter. But bigger isn’t always better. That’s why we also sell broadheads with cutting diameters between 1” and 1-1/4”. As the cutting surface of a broadhead increases, penetration ability decreases. In his article “Hunting Arrows,” published in Ye Sylvan Archer in 1943, Fred Bear wrote, "A deer can be killed with most any combination if no heavy bones are struck but what is needed is something that will crash through where the going is tough." And in a 10-year study called Momentum, Kinetic Energy, and Arrow Penetration (And What They Mean for the Bowhunter) by Dr. Ed Ashby, it’s stated, “Lack of penetration is the number one cause of a hit being non-lethal.”

After all, the deeper your broadhead penetrates, the more damage it does. Cutting diameter is only one variable in the penetration equation, but it is one that is easily overlooked. Oftentimes, thanks to broadhead commercials and ads, bowhunters, especially young bowhunters, immediately associate a bigger cutting diameter to better penetration. But, selecting the proper cutting diameter is not about what is “cool” or what you see on TV. It’s a matter of selecting the right broadhead for your setup.

Kinetic Energy

The kinetic energy output of your arrow is a factor of velocity and weight. A good start to choosing a broadhead with the proper cutting is to determine how much kinetic energy your arrow has when it meets its target (click here for a guide to determining kinetic energy). Below is a chart for choosing the best broadhead for the amount of kinetic energy a hunter’s bow and arrow setup has for deer hunting:

Kinetic Energy Output

Fixed-Blade Broadheads

Mechanical Broadheads

30-39  ft-lbs

Any broadhead in our fixed-blade catalog will be plenty efficient to make the most use of available kinetic energy with the exception of the 4-blade models.

Not recommended for bows and arrow setups producing less than 40 ft-lbs of kinetic energy.

40-49 ft-lbs

Any Wasp fixed-blade broadhead

Jak-Hammer SST 1-1/4"

Rack Attack Mechanical

50-59 ft-lbs

Any Wasp fixed-blade broadhead

Jak-Hammer SST 1-1/4"

Rack Attack Mechanical

Z-Force

60+ ft-lbs

Any Wasp fixed-blade broadhead

Any Wasp mechanical broadhead

 

Broadhead Design and Blade Sharpness

Notice we did not just give recommended cutting diameters in the broadhead selection chart above. That is because the broadhead’s design – slope of the blades, blade configuration, etc. – is responsible for making efficient use of the cutting diameter. Different broadheads with the same cutting diameter produce different penetration results. Wasp Archery broadhead designs have been proven for more than four decades. In fact, we‘ve been known to have the most aerodynamic broadhead and sharpest blades.

It’s often assumed that broadhead blades are sharp. They will all probably shave hair from your arm. However, you’d be surprised how many of our competitor’s blades are at a disadvantage right out of the package. A dull broadhead will not do the job as efficiently as a sharp one no matter what type. In the end, it all comes do pushing razor-sharp blades through the vitals of an animal, or as Fred Bear said, “…something that will crash through where the going is tough." Below is how Wasp Archery blades faired against its competitors in head-to-head broadhead test done by Petersen’s bowhunting magazine:

The Razor Edge Sharpness Test (REST) machine was rented from CATRA to measure blade sharpness. The machine measures the force, in Newtons, required to cut through a rubber test medium. The rubber test material is threaded through a roller fixture, which exposes the face of the 3-millimeter material and places it under tension at the blade interface. The roller fixture is motor driven and approaches the stationary, vise-mounted blade. When the blade contacts the test material, the pressure increases until the surface is cut. The peak force required to break the surface is recorded. The less force needed to cut, the sharper the blade. Three blades from each broadhead model (one blade from three different heads) were tested. To give you some reference points, we also tested a utility knife blade, a very sharp Buck knife that easily shaves hair and a fairly sharp SOG knife.

While a broadhead’s ability to penetrate is fairly dependent on its cutting diameter, other factors are also responsible for penetration. Wasp is confidant our design makes the most of any available kinetic energy going through a target. A wide-cutting mechanical is nice to have to increase tissue and the insurance of hitting the vitals if you have an adequate supply of kinetic energy, but it will actually hinder penetration and lethal kills if you don’t have the power to push it through to the vitals and break though ribs and bone.

With the amount of broadheads commercially available today, a bowhunter has to make educated decisions when it comes time to pick out what broadhead will work best on the end of their arrow. It’s our responsibility as sportsman to make sure we are outfitted to make a compassionate kill. If you have any questions about what cutting diameter or broadhead will work best for you, comment below or ask us on Facebook or Twitter. Or, make it easy and choose the new Wasp Drone, a broadhead we know will kill a deer with a well-placed shot when fired from any bow with at least 30 lb-ft of kinetic energy.