THE 6.5 CREEDMOOR CARTRIDGE MASTER COMPENDIUM » TN-06 — Throat Erosion in 6.5 Creedmoor

I. What Throat Erosion Is & Why It Matters

The throat—the short, unrifled transition between chamber and rifling—experiences the highest thermal and pressure stress of the entire rifle system.

In 6.5 Creedmoor, erosion is driven by:

  • Powder temperature & burn rate
  • Charge density relative to bore volume
  • Rapid heat cycles during long shot strings
  • Bullet diameter and bearing surface length
  • Gas jetting during the first microseconds of ignition

As erosion develops:

  • Jump increases
  • Pressure curve shape changes
  • Accuracy nodes shift
  • Vertical dispersion appears
  • ES/SD can slowly rise

II. How Erosion Progresses in 6.5 Creedmoor

Typical phases:

  • Phase 1 (0–400 rounds) — initial wear-in; tooling marks smooth out
  • Phase 2 (400–1,800+) — stable precision window
  • Phase 3 (1,800–2,800+) — measurable throat recession; seating depth adjustments restore nodes

Borescope indicators include:

  • Micro-cracking in first 0.2–0.4″
  • Frosted appearance
  • Asymmetric erosion
  • Slight freebore enlargement

III. Heat Cycles: The True Barrel Killer

Erosion depends on rounds × heat, not round count alone. Creedmoor barrels experience:

  • High sustained throat temperatures in PRS competition
  • Longer dwell time with H4350/RL-16 class powders
  • Significant heat soak in heavy profiles

Effect:

  • Hunters may see decade-long life
  • PRS shooters may lose 25–35% life from aggressive strings

IV. Seating Depth Drift & How to Track It

Erosion increases jump over time, affecting:

  • Optimal seating depth
  • Node stability
  • Vertical consistency

Signs of drift:

  • Original tune no longer yields lowest ES/SD
  • Slight vertical tails in groups
  • Measured lands recession over time

V. Technical Notes Directly Linked to TN-06

Specifications

  • Technical Note: TN-06 — Throat Erosion in 6.5 Creedmoor
  • Category: Wear & Barrel Life
  • Focus: Heat cycles, round-count behavior, erosion patterns
  • Primary Links: TN-01, TN-02, TN-03, TN-04, TN-07, TN-11
  • Compendiums: Cartridge & Rifle Master Compendiums