1. What is FPE?

FPE (Foot-Pounds of Energy) is a unit of measurement for the kinetic energy of a projectile. It represents the amount of energy delivered upon impact and is commonly used in ballistics and airgun applications.

2. How Does the Calculator Work?

The calculator uses the FPE formula:

Where:

• \( Mass \) — Projectile weight in grains
• \( FPS \) — Velocity in feet per second
• 450240 — Conversion factor (2 × 7000 grains/lb × 32.174 ft/s²)

Explanation: The equation calculates kinetic energy by squaring the velocity and multiplying by mass, then converting to foot-pounds.

3. Importance of FPE Calculation

Details: FPE is crucial for understanding projectile effectiveness, comparing different ammunition, and ensuring compliance with local regulations for hunting or target shooting.

4. Using the Calculator

Tips: Enter projectile mass in grains and velocity in feet per second. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why use grains for mass measurement?
A: Grains are the standard unit for measuring projectile mass in ballistics (1 grain = 1/7000 pound).

Q2: What's a typical FPE for airguns?
A: It varies widely - from under 10 FPE for target pistols to over 100 FPE for big bore hunting airguns.

Q3: How does FPE relate to stopping power?
A: While FPE measures energy, other factors like projectile design and shot placement also affect stopping power.

Q4: What's the difference between FPS and FPE?
A: FPS measures velocity (speed), while FPE measures energy. A lighter projectile may have higher FPS but lower FPE than a heavier one.

Q5: Is there a maximum FPE limit for hunting?
A: Some regions regulate maximum FPE for certain types of firearms or hunting applications - always check local laws.