Optimizing FOC for Accuracy and Penetration

In archery, the “Front of Center” (FOC) refers to the percentage of an arrow’s weight that is concentrated in front of the center of the arrow.  An arrow’s FOC influences its flight characteristics, stability, and penetration upon impact. Having an appropriate balance between FOC and arrow weight is important for maximizing arrow flight and performance.  It can affect factors such as arrow stability, arrow spine, and the momentum of the arrow at the target. 

Arrow Build

HOW DOES FOC AFFECT ARROW FLIGHT

FOC plays an important role in arrow flight having a significant impact on its overall performance. The FOC percentage can be increased by concentrating weight towards the front of the arrow, which contributes to enhanced stability and improved accuracy during flight. This distribution of weight allows the fletchings to exert more influence on the arrow’s stabilization, reducing the disruptive effects of external forces such as wind.

It is important to note that increasing arrow weight to improve momentum may come at the expense of trajectory. Also, adding weight to the front end of an arrow weakens its spine. Potentially causing inconsistency and accuracy issues. This can be fixed by switching to a stiffer arrow however, that will likely result in an increase in arrow mass.  Despite this trade-off, many archers prioritize higher FOC at the cost of increased arrow mass due to its increased penetration capabilities.

Dr. Ed Ashby’s 2019 Terminal Arrow Performance Update, emphasized the importance of finding the right balance between arrow weight and trajectory. He recommended utilizing the heaviest arrow possible while still maintaining an acceptable trajectory. This approach aims to optimize the arrow’s momentum and penetration without compromising its flight characteristics.  According to Dr. Ashby’s research, increasing FOC is one of the most effective ways to increase arrow performance. 

IDEAL FOC FOR HUNTING

The question of the best FOC percentages for hunting is akin to asking about the best caliber rifle for hunting. Just as there are various factors to consider when choosing a rifle, selecting the right arrow setup with optimal FOC requires consideration of multiple factors.

Easton Archery recommends a FOC range of 7%-15% for target archery and 10%-15% for hunting applications. These ranges provide a good starting point for most archers looking to achieve a balance between accuracy and penetration.

On a similar note, well-known bowhunter Travis “T-Bone” Turner of Bone Collector suggests a slightly higher FOC range of 15%-20% for hunting. T-Bone’s preference for a higher FOC percentage is attributed to his years of experience hunting big game animals. In his setup, T-Bone’s arrows weighed around 510 grains after adjusting for the desired FOC.

Extreme FOC Percentages

Dr. Ed Ashby, known for his extensive research on arrow performance, provides yet another perspective on the subject.  Dr. Ashby studied arrow setups from several primitive tribes in different countries. His findings revealed that a majority of the arrows used by these tribes had FOC values in the 30%-40% range. This indicates that historically, higher FOC percentages were commonly employed. 

According to Dr. Ashby’s metric, arrows with a FOC between 19% to 30% fall into the category of Extreme FOC (EFOC), while a FOC exceeding 30% is classified as Ultra-Extreme FOC. Dr. Ashby’s research has discovered that arrows utilizing Extreme or Ultra-Extreme FOC (Ultra-EFOC) percentages exhibit improved flight quality and demonstrate notably higher penetration levels.

The remarkable convergence of high FOC arrow designs across diverse tribes from various geographic locations serves as compelling evidence for the role of FOC in arrow performance and penetration.  This underscores the significance of FOC as a fundamental component that transcends cultural and geographical boundaries, making it a universal principle in bowhunting. 

HOW TO FIND THE FOC

Calculating FOC involves determining the percentage difference between the arrow’s center of gravity, or balance point, and its center. A higher FOC percentage indicates the balance point is closer to the arrow’s front, while a lower percentage suggests there is more weight toward the rear.

To measure the FOC of an arrow, follow these steps:

1. Measure the overall length of the arrow from the throat of the nock to the end of the arrow shaft, excluding the point.

2. Install all components on the arrow, including the point or broadhead.

3. Find the balance point of the arrow by suspending it on a fulcrum and adjust until it balances perfectly.

4. Measure the distance from the balance point to the throat of the nock.

5. Input these measurements into a FOC calculator or use the following formula:  

Determining FOC

Optimizing FOC

Attaining the desired FOC balance requires thoughtful adjustments to various components of the arrow. To increase the FOC percentage, archers must consider augmenting the weight at the front of the arrow while simultaneously reducing the weight towards the rear if possible. Several strategies can help achieve this balance and optimize arrow performance.

To increase the front weight of the arrow, archers can employ various methods such as using heavier points or broadheads, installing heavier inserts, or utilizing a combination of both. This additional weight shifts the balance point towards the front, enhancing the FOC percentage. Keep in mind, adding weight to the front of an arrow will weaken its spine and may contribute to poor arrow performance.  Experimenting with different point weights and inserts allows archers to fine-tune the arrow’s weight distribution suitable for their arrow’s spine and according to their preferences.

Similarly, reducing the weight at the rear of the arrow can contribute toward achieving the desired FOC balance. This can be achieved by removing arrow wraps or transitioning from four vanes to three, effectively reducing material and weight at the rear of the arrow.

Also, modifying the arrow’s length may contribute to increasing the FOC percentage as cutting the arrow shorter can shift the balance towards the front. 

Maximizing Arrow Performance by optimizing FOC IS ACCESSIBLE TO EVERY ARCHER

After exploring the significance of Front of Center (FOC), it is easy to see how it is a critical aspect of arrow performance.  Not only can FOC impact an arrow’s flight characteristics, but it also holds the potential to enhance stability, accuracy, and penetration by shifting weight toward the front of the arrow.  Fortunately, finding an arrow’s FOC does not require advanced tools or technical expertise, making it accessible to every archer.  By understanding the simple steps of measuring and adjusting FOC, bowhunters of all skill levels can optimize their arrow setup with a proper balance of penetration and trajectory suitable for their hunting preference.  With this knowledge, archers can maximize the potential of their arrow setup and greatly improve their hunting experience.  

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