Mechanical Broadheads: Design, Function & Benefits

Mechanical broadheads — also called expandable broadheads — are arrowheads with blades that fold flat against the ferrule during flight and deploy outward upon impact. This collapsible design reduces wind drag and keeps the arrow's flight path closer to that of a standard field tip, making them among the most aerodynamic broadhead options available.

How Mechanical Broadheads Work

Collapsible Design

During flight, the blades retract into a streamlined shape, minimizing surface area and air resistance. They are typically held closed by small metal pins or rubber bands that break on contact with the target, allowing the blades to swing or fold outward freely. Because of this consistency in flight, archers often find that mechanical blades archery setups require less tuning adjustment compared to fixed-blade broadheads.

Deployment Styles

Modern mechanical broadheads fall into two main deployment categories. Over-the-top (front-deploying) heads have blades hinged at the rear of the ferrule that pivot forward upon contact, opening after initial penetration to cut through vitals with maximum sharpness. Rear-deploying heads have blades that pivot from the front and open before reaching the vitals, producing full-size entrance and exit holes that maximize blood trails. Some designs use two blades that swing to the sides; others use three or more blades that fold out like a fan.

Advantages of Expandable Blades for Hunting

Accuracy

Because expandable broadheads fly more like field tips, they are more forgiving of minor bow setup imperfections such as slightly misaligned arrows or bowstring inconsistencies. They are also typically lighter than fixed-blade arrowheads, which can contribute to higher arrow speed and flatter trajectory.

Wound Channel and Penetration

Upon impact, mechanical arrowheads expand to create a larger wound channel than a closed blade could produce in flight. Cutting diameters on some designs reach over two inches, which increases the likelihood of a clean kill and creates a more visible blood trail for tracking. When hunting larger, bigger-boned animals, a smaller cutting diameter generally delivers better penetration.

Tuning Considerations

Even though mechanical broadheads are more forgiving in flight, proper bow tuning remains essential. A minimum of 40 foot-pounds of kinetic energy is the widely cited threshold for reliable blade deployment and adequate penetration. Always perform a spin test after installing any broadhead or arrowhead to confirm the combination is seated true and wobble-free before hunting. For background on how broadheads relate to other arrow point styles, see our broader glossary entries.