IRON NESTGuides

Shell mechanics

How Gas, Suppression, and Fire Shells Work

Choose these shells by the effect you need: suppression, suppression-dependent lethality, or fire.

Quick answer

Use TEAR to reveal and suppress. PHGN is reported as lethal against targets that are already suppressed. WP combines that suppression-dependent interaction with possible fire spread, while INCN is the more direct incendiary option. For the Fire on Call request, use TEAR before HE.

How to use these shells

  1. Reveal and suppress with TEAR

    Use TEAR when the goal is to reveal and suppress targets rather than kill them immediately.

  2. Follow suppression with PHGN

    Multiple independent post-release guides agree that PHGN becomes lethal against targets that are already suppressed.

  3. Use WP for the combined interaction

    WP is reported to have the same suppression-dependent lethal interaction while also creating a chance of secondary fire spread.

  4. Use INCN as the direct fire option

    INCN is the more direct incendiary choice when fire and possible secondary spread are the main goal rather than a suppression interaction.

  5. Treat roughly 50% as an empirical estimate

    One documented version 1.0 (1577) test observed at least one spread event on 12 of 25 WP shots and 13 of 25 INCN shots. A separate post-release guide independently described both at roughly 50%; neither source establishes an exact internal probability.

  6. Fire on Call — use TEAR first, then HE

    For the Fire on Call support request that explicitly asks for TEAR followed by HE, follow that order. The structured mission-data extract includes a failure state when HE lands before TEAR takes effect. This is a mission-specific sequence, not a universal damage combo.

THRM warning: the roughly 50% fire-spread figure is an observation, not proof of the internal probability. THRM failed to spread fire in the documented test sample. The broader shell interactions come from independent early-1.0 reports rather than a direct version 1.0 (1618) retest.

Common mistakes

  • Treating the roughly 50% spread estimate as a guaranteed exact probability.
  • Planning around an invented duration for gas, suppression, or fire states.
  • Assuming Patch #4 changelog silence proves the early-1.0 behavior is unchanged in version 1.0 (1618).
  • Generalizing Fire on Call's required TEAR-then-HE support sequence to every target or mission.
Why these interactions work

Two independent early-post-release community guides report the same practical interaction model. One documents finite version 1.0 (1577) samples, while the other independently describes approximately 50% spread. Both direct guide pages are currently marked removed from Steam Community; the reason is not established. A current structured Fire on Call mission-data extract separately documents one support call that requires TEAR before HE. That mission-specific order does not establish a universal damage multiplier, armor effect, duration, or optimal sequence.

Practical interaction model corroboratedCorroborated scopeChecked Aug 14, 2026

Two independent post-release guides agree on the broad interaction model, and structured mission data directly documents TEAR before HE for one Fire on Call support request. The global interaction evidence remains empirical and provenance-degraded.

Version context: Independent early-1.0 community observations plus a current structured Fire on Call mission sequence; no direct version 1.0 (1618) human retest

Still uncertain

  • Exact internal fire-spread probabilities
  • Duration of gas, suppression, and fire states
  • Direct version 1.0 (1618) retest
  • Why both detailed Steam Community guide pages were removed
  • Whether any TEAR-to-HE sequence outside the named Fire on Call support request is required or advantageous

Evidence and verification context

  • Everything Ammo — version 1.0 (1577) test: Captured finite tests and the interaction model, including WP 12/25, INCN 13/25, and THRM 0/14. Its direct Steam Community page is currently marked removed.
  • Shell Effects Catalogue — independent post-release guide: Independently corroborates suppression-dependent lethality, approximate WP/INCN spread, and the THRM mismatch. Its direct Steam Community page is also currently marked removed.
  • Official Patch #4 notes: Do not list ammunition changes, but changelog silence is not treated as proof that early-1.0 behavior remained unchanged in version 1.0 (1618).
  • Current Fire on Call mission sequence: The independent structured game-data extract directly records a Fire on Call support request for TEAR followed by HE and a failure state when HE lands before TEAR takes effect. It supports only that mission-specific order.