Each recipe is orange until its yellow rank and grey from its grey rank. When the ranks differ, it turns green somewhere between the two; the client files give both ranks but not that point. Equal ranks go straight to grey.

Engineering: Ammunition
RecipeMakesReagentsNeedsSkill-up
Crafted Light Shot
200 × Crafted Light ShotYellow 30Grey 60
Crafted Heavy Shot
200 × Crafted Heavy ShotYellow 85Grey 95
Crafted Solid Shot
200 × Crafted Solid ShotYellow 125Grey 145
Explosive Arrow
100 × Explosive Arrow
  • Arclight Spanner
  • Gyromatic Micro-Adjustor
Yellow 210Grey 250
Hi-Impact Mithril Slugs
200 × Hi-Impact Mithril Slugs
  • Blacksmith Hammer
  • Anvil
Yellow 210Grey 250
Mithril Gyro-Shot
200 × Mithril Gyro-Shot
  • Blacksmith Hammer
  • Anvil
Yellow 245Grey 285
Thorium ShellsTaught by Schematic: Thorium Shells, requires 285
200 × Thorium Shells
  • Blacksmith Hammer
  • Anvil
Yellow 305Grey 325
Swiftfeather ArrowTaught by Schematic: Swiftfeather Arrow, requires 300
200 × Swiftfeather Arrow
  • Anarchist's Workbench
Yellow 310Grey 320
Swiftstrike ShotTaught by Schematic: Swiftstrike Shot, requires 300
200 × Swiftstrike Shot
  • Anarchist's Workbench
Yellow 310Grey 320

From the Forever beta client files, build 1.60.1.70630: the SkillLine, SkillLineAbility, TradeSkillCategory, SpellReagents, SpellEffect, SpellTotems, SpellCastingRequirements and ItemEffect tables.