- Enter values to see required velocity and weight targets.
| Weight (gr) | Velocity (fps) | Power Factor | Typical outcome* |
|---|---|---|---|
| 115 | 1100 | 126.5 | Often clears Minor |
| 124 | 1050 | 130.2 | Minor with buffer |
| 147 | 900 | 132.3 | Minor, softer feel |
| 180 | 950 | 171.0 | Often reaches Major |
Power factor uses weight (gr) and velocity (fps):
- 1 g = 15.4323583529 gr
- 1 m/s = 3.2808398950 fps
- Momentum and kinetic energy are shown for context.
- Enter bullet weight and choose units.
- Enter velocity and choose fps or m/s.
- Select a threshold preset, or use custom.
- Review PF, classification, and required targets.
- Export CSV or PDF for documentation.
Understanding bullet power factor
Bullet power factor (PF) is a momentum-style score used in action shooting sports to separate “Minor” and “Major” scoring. It combines bullet weight in grains and muzzle velocity in feet per second. A higher PF can improve scoring category requirements, while a lower PF often feels softer and may reduce recoil, depending on your overall setup.
Inputs that change the result
PF moves linearly with both inputs, so small changes matter. Typical handgun bullets range from about 90–230 gr, and velocities commonly sit between 750–1,400 fps. Because the calculation multiplies these values, a 2% velocity swing produces a 2% PF swing, even if the bullet weight is fixed.
Worked example using the formula
Use PF = (Weightgr × Velocityfps) ÷ 1000. For a 124 gr load at 1,050 fps: PF = (124 × 1050) ÷ 1000 = 130.2. If your match requires PF 125, this clears the floor. To reach PF 165 with the same 124 gr bullet, you would need about 1,331 fps (165 × 1000 ÷ 124).
Minor and Major thresholds
Many competitors reference common breakpoints like 125 for Minor and 165 for Major, but the exact threshold depends on the sport, division, and local rules. The calculator’s presets and custom threshold option let you label your load quickly and keep notes for different matches.
When your data is in metric units
If your chronograph reads meters per second and you log bullet mass in grams, convert before calculating. Example: 8.0 g is about 123.5 gr, and 320 m/s is about 1,049.9 fps. That yields PF ≈ (123.5 × 1049.9) ÷ 1000 ≈ 129.6, which is typically Minor in many rule sets.
Building a safe buffer
Chronograph variance, temperature, and lot-to-lot powder changes can lower velocity on match day. Many shooters aim for a cushion of 2–5 PF above the minimum. If your floor is 125, targeting 128–130 reduces the chance of failing chrono while keeping recoil reasonable.
Practical workflow and record keeping
Measure velocity with a chronograph, average multiple shots, then enter weight and velocity here. Review the PF output, the classification label, and any “required velocity” guidance. Export CSV for a load log, or generate a PDF for match documentation and range notes.
FAQs
What is power factor used for?
It’s used to categorize ammunition for scoring or compliance in some competitions. The calculation combines bullet weight and velocity, helping you label a load as Minor or Major based on a chosen threshold.
Does a higher power factor always mean more recoil?
Not always, but higher PF usually comes from higher momentum, which can increase recoil. Firearm weight, compensators, springs, and powder burn rate also affect the feel, so compare loads with the same platform.
How many shots should I average for velocity?
Five to ten shots is a common starting point for a stable average. More shots reduce random spread. Record temperature and barrel length, because both can change velocity and your final PF.
Can I calculate power factor with grams and m/s?
Yes. Convert grams to grains and meters per second to feet per second, then apply the formula. This calculator can convert inputs so you can enter data the way your chronograph logs it.
What buffer should I keep above the minimum PF?
Many shooters aim for 2–5 PF above the floor to account for chronograph differences and environmental changes. If your minimum is 125, targeting around 128–130 is a common cushion.
Is this calculation the same as muzzle energy?
No. Power factor scales with momentum (mass × velocity). Muzzle energy scales with velocity squared, so it rises much faster with speed. Use an energy calculator when you need joules or foot‑pounds.