Tier 1 - Crafted equipment grants an additiona; equipmentt if able.
Tier 2 - All enemies have a small chance to drop ammo
Tier 3 - Stowed weapons slowly refill ammo from stock
Tier 4 - 25% chance to keep non-retrievable equipment when used
Tier 5 - 3rd primary weapon is recovered when repurchasing Mule Kick