BALLISTIC_F.O.C._LAB

50% CENTER

BALANCE POINT

1. SHAFT & SPEED

SHAFT LENGTH IN

SHAFT GPI GN

SPEED (FPS) FPS

LOCK BASELINE FOR SPEED DECAY

Check this to simulate FPS loss as you add weight (-1 FPS per 3gn).

2. FRONT END WEIGHT

POINT 75 | 100 | 125 | 150 GN

INSERT 20 | 50 | 75 | 100 GN

3. REAR END WEIGHT

NOCK STD | LIT GN

VANE WT (EA) GN

QTY PCS

WRAP GN

ACTIVATE ADVANCED CENTROID MATH

TOTAL WEIGHT

0 GN

EFFECTIVE VELOCITY

0 FPS

SIMULATED F.O.C.

0.00%

KINETIC ENERGY

0 FT-LBS

MOMENTUM

0 SLUG-FPS

KINETIC REFERENCE CHART (EST)

SMALL GAME

MEDIUM GAME

LARGE GAME

DANGEROUS

ⓘ

Calculated values are theoretical. Real-world lethality is determined by shot placement and broadhead efficiency. User assumes all responsibility.

DIGITAL QUIVER (SAVE YOUR BUILDS)

04. DEFINITION

FOC (Front of Center) is the percentage of the arrow's total weight located in the front half of the shaft. It is the primary driver of down-range accuracy and penetration potential.

Adding weight to the tip pulls the balance forward (raising FOC). Adding weight to the back pulls it backward (lowering FOC). Precision builds typically fall within the 7% to 15% window.

05. THE ALGORITHM

FOC % = [ ( L_bal - L_tot/2 ) / L_tot ] × 100

L_bal = Balance Point Location | L_tot = Total Arrow Length

06. PHYSICAL VALIDATION PROTOCOL

01 MEASURE LENGTH

Measure the total arrow length from the throat of the nock to the end of the shaft (or point tip, depending on method preference).

02 LOCATE BALANCE

Place the arrow on a thin edge (a knife edge or ruler). Find the exact point where the arrow hovers level. Mark this spot.

03 RECORD DATA

Measure the distance from the throat of the nock to your balance mark. This is your Center of Gravity (COG).

04 CALCULATE

Input your Total Length and Balance Point into the formula above to verify results.

07. EXAMPLE ARCHIVES

THE WHITETAIL STANDARD

Balanced speed and penetration. Perfect for most North American game. (~11% FOC)

Point: 100gn | Insert: 20gn
Shaft: 8.5 GPI @ 28.5"

HEAVY BONE BREAKER

Maximum kinetic energy and high FOC for heavy game like Elk or Moose. (~16% FOC)

Point: 125gn | Insert: 50gn
Shaft: 9.5 GPI @ 29"

WESTERN SPEED FREAK

Flatter trajectory for long-range western hunting like Mule Deer. (~9% FOC)

Point: 100gn | Insert: 15gn
Shaft: 7.5 GPI @ 28"

08. F.A.Q. DEBRIEF

What is a good F.O.C. for hunting Deer?

For standard compound bows hunting whitetail or mule deer, a target F.O.C. of 10% to 15% is generally considered the "sweet spot". This gives you a great balance: enough forward weight to stabilize the broadhead and pull the arrow straight through the animal, without sacrificing too much trajectory (speed) over standard hunting distances (20-40 yards).

Does High F.O.C. ruin my arrow's flight trajectory?

It depends on how extreme it is. Pushing into the 15% - 18% range won't ruin your flight, but your arrow will drop slightly faster at distances beyond 40 yards because you've added mass to the front. Extreme F.O.C. (20%+) can cause arrows to "nose-dive" at longer ranges, making your pin gaps much wider. You have to balance penetration needs with the distances you expect to shoot.

What happens if my F.O.C. is too low?

An F.O.C. below 7% can lead to erratic arrow flight, especially when shooting fixed-blade broadheads. Because the center of mass is too close to the middle of the arrow, the steering from the broadhead in the front competes too heavily with the steering from the vanes in the back. This results in poor accuracy and massive losses in penetration energy upon impact.

Should I just add a heavier point to increase F.O.C.?

You can, but you must be careful not to weaken the dynamic spine of your arrow. Adding weight to the front of an arrow makes it bend (flex) more upon release. If you add a 150-grain point to a 400-spine arrow that was meant for a 100-grain point, the arrow will fly erratically because it is now underspined. Always check an archery spine chart before drastically increasing front weight.