Broadhead Confidence Calculator — Is Your Build Enough for the Animal You're Hunting?

The question every hunter asks the night before opening day: is my arrow enough? The honest answer is not a single number. It's a stack of numbers. Kinetic energy, momentum, FOC, broadhead mechanical advantage, and the specific game class you're hunting.

The Forge's Broadhead Confidence Score runs all of that for you across 8 game classes and tells you exactly where you stand.

What the Broadhead Confidence Score is

It's a single grade per game class that weighs four factors against published thresholds:

  • Kinetic energy at the animal's distance
  • Momentum at impact
  • FOC and its effect on penetration depth
  • Broadhead type and mechanical advantage

It outputs a band: HIGH, ADEQUATE, MARGINAL, or INSUFFICIENT. One look tells you whether to take the hunt or rebuild your arrow.

Why kinetic energy alone is not enough

For decades, the hunting industry leaned on KE as the single metric. Easton's tables. Outdoor magazines. The advice was: hit 42 ft-lb for elk and you're set.

Then Dr. Ed Ashby ran two decades of penetration tests on dead game at the Natal Game Ranch in South Africa. His finding: momentum, FOC, and broadhead mechanical advantage matter more than KE once the basic energy threshold is met. A 650-grain arrow with 19% FOC and a single-bevel head outpenetrates a 400-grain arrow with the same KE by a wide margin. On bone, it's not even close.

The 2025 Yates broadhead study confirmed Ashby's framework with modern data: bone breach correlates with momentum and tip geometry more than raw KE.

The thresholds per game class

The Forge uses these thresholds, drawn from Easton's published recommendations and the Ashby tier system:

  • Turkey: 25 ft-lb KE, 0.30 momentum. Mechanical or fixed heads both fine.
  • Whitetail / pronghorn: 30 ft-lb KE, 0.40 momentum. Cut-on-contact preferred; mechanical acceptable.
  • Mule deer / sheep: 35 ft-lb KE, 0.45 momentum. Same as whitetail with a bit more margin.
  • Black bear / hog: 42 ft-lb KE, 0.50 momentum. Fixed two-blade or single-bevel preferred. Hogs especially need bone-breaching capability.
  • Elk: 50 ft-lb KE, 0.55 momentum, 12%+ FOC. Single-bevel fixed strongly preferred.
  • Moose: 65 ft-lb KE, 0.62 momentum, 15%+ FOC. Heavy single-bevel.
  • Brown bear / grizzly: 70 ft-lb KE, 0.65 momentum, 15%+ FOC. Single-bevel, total arrow 600+ grains.
  • Cape buffalo / dangerous game: 85 ft-lb KE, 0.78 momentum, 19%+ FOC (Ashby Ultra-EFOC). Single-bevel only, total arrow 650+ grains.

The math behind the score

For each game class, the Score calculates:

  • KE margin = (your KE - threshold KE) / threshold KE
  • Momentum margin = (your momentum - threshold momentum) / threshold momentum
  • FOC factor = your FOC / target FOC for the class (capped at 1.3)
  • Broadhead factor = mechanical advantage multiplier (1.0 baseline for two-blade fixed, 1.15 for single-bevel, 0.85 for mechanical on heavy bone game)

These combine into a confidence index. Above 1.25, you score HIGH. 1.00 to 1.25 is ADEQUATE. 0.85 to 1.00 is MARGINAL. Below 0.85 is INSUFFICIENT.

The bands are calibrated against the Easton minimums (as the floor), the Ashby penetration tier system (as the upper benchmarks), and the 2025 Yates study's bone-breach data.

A real example

A client this spring wanted to know if his whitetail rig would work for a fall elk hunt. His build:

  • Hoyt Carbon RX-8, 62-pound draw, 28-inch draw length
  • Easton 4MM Axis 300, cut to 28.5 inches
  • 125-grain field point, 50-grain steel insert
  • Total weight 462 grains, FOC 13.2%, chronograph 282 fps
  • Planned broadhead: Iron Will S-125 single-bevel

The Forge ran his numbers:

  • KE: 81.7 ft-lb
  • Momentum: 0.578 slug-ft/s
  • Broadhead factor: 1.15 (single-bevel)
  • Elk threshold: 50 ft-lb, 0.55 momentum, 12% FOC
  • Confidence index for elk: 1.42 = HIGH
  • Confidence index for moose: 1.09 = ADEQUATE
  • Confidence index for cape buffalo: 0.81 = INSUFFICIENT

Translation: take the elk hunt with confidence. Could handle a Canadian moose if needed. Not built for buffalo, which he wasn't hunting anyway.

What changes the score most

The single biggest lever is total arrow weight. Adding 60 grains via a heavier insert or point moves momentum more than it costs in KE. The next biggest lever is broadhead choice. A single-bevel fixed head on heavy game adds 15% to your confidence factor over a mechanical. FOC matters but moves slower; getting from 11% to 14% adds meaningful margin on elk and above.

How to run your own score

Open The Forge, build or load your arrow, drop your chronograph velocity, pick your broadhead from the database (every major head from Iron Will, VPA, Cutthroat, Day Six, Magnus, Slick Trick, G5, QAD, Rage, Sevr is in there), and the Score appears across all 8 game classes.

Hunter tier ($6/month) unlocks the full Confidence Score with all 8 classes, unlimited builds, and the ability to A/B compare different setups side by side. Free tier shows turkey, whitetail, and elk.

FAQ

Is my arrow enough for elk?

Run the Score. The published floor is 42 ft-lb KE and roughly 0.50 momentum. Most modern 60-pound compounds with a 450+ grain arrow and a quality fixed head will land in HIGH for elk.

Why does broadhead type affect the score?

Mechanical advantage. A single-bevel cut-on-contact head wedges through bone with rotational force. A mechanical head dumps energy opening and has narrower margin on heavy bone. The Score reflects that with a multiplier.

What's the difference between MARGINAL and INSUFFICIENT?

MARGINAL means a perfect shot will kill cleanly but you have zero margin for a quartering angle or shoulder contact. INSUFFICIENT means do not take this animal with this setup.

Does FOC really change penetration that much?

Yes. Ashby's data shows penetration depth scales meaningfully with FOC above 12%, and exponentially above 19%. The Score weights FOC as a multiplier on momentum.

Is the score calibrated for traditional bows?

Yes. The math is the same. Trad shooters typically run heavier arrows and higher FOC by default, which often produces a better Confidence Score than a fast compound on the same animal.

Where do the thresholds come from?

Easton's published game-class KE minimums, Ed Ashby's two-decade penetration study at Natal Game Ranch, and the 2025 Yates broadhead study on bone breach. The Forge cites the sources in the Score detail view.