A tactical event (Also known as a "Private Battle" in the United Kingdom and elsewhere) is a type of historical reenactment, not usually open to the public, which is fought like a real battle with each side devising strategies and tactics to defeat their opponent(s). Tactical events have no script, a basic set of agreed-upon rules (physical boundaries, time limit, victory conditions, etc.
A simulated conflict (Also known as a "Private Battle" in the United Kingdom and elsewhere) is a type of historical reenactment, not typically open to the public, where participants engage in a battle-like scenario with each side developing strategies and tactics to outmaneuver their opponents. Simulated conflicts are governed by a set of unwritten rules (physical boundaries, time limits, victory conditions, etc.).