Echo Storm

• WWizards of the Coast2018-07-13
  Official Ruling
  If the copied artifact is copying something else (for example, if the copied artifact is a Sculpting Steel), then the token enters the battlefield as whatever that artifact copied.
• WWizards of the Coast2018-07-13
  Official Ruling
  The token copies exactly what was printed on the original artifact and nothing else (unless that artifact is copying something else or is a token; see below). It doesn't copy whether that artifact is tapped or untapped, whether it has any counters on it or Auras attached to it, or any non-copy effects that have changed its types, color, or so on.
• WWizards of the Coast2018-07-13
  Official Ruling
  Each Storm's triggered ability can copy the Storm spell even if that spell is countered before that ability resolves.
• WWizards of the Coast2018-07-13
  Official Ruling
  The copies are created on the stack, so they're not “cast.” Abilities that trigger when a player casts a spell (such as the Storm's ability itself) won't trigger.
• WWizards of the Coast2018-07-13
  Official Ruling
  If the copied artifact is a token, the token that's created copies the original characteristics of that token as stated by the effect that created the token.
• WWizards of the Coast2018-07-13
  Official Ruling
  Each copy resolves one at a time. Any abilities that trigger on the artifact token entering the battlefield resolve before the next copy resolves. The original spell is the last to resolve.
• WWizards of the Coast2018-07-13
  Official Ruling
  If the copied artifact has in its mana cost, X is considered to be 0.
• WWizards of the Coast2018-07-13
  Official Ruling
  Each Storm's triggered ability counts only how many times you've cast your commander from the command zone before that triggered ability resolves. If you cast your commander again later, you won't get another copy.
• WWizards of the Coast2018-07-13
  Official Ruling
  Any enters-the-battlefield abilities of the copied artifact will trigger when the token enters the battlefield. Any “as [this artifact] enters the battlefield” or “[this artifact] enters the battlefield with” abilities of the chosen artifact will also work.
• WWizards of the Coast2018-07-13
  Official Ruling
  If your commander was countered, that time you cast it still counts.
• WWizards of the Coast2018-10-05
  Official Ruling
  If you have multiple commanders, you'll copy this spell for each time you've cast either of them. For example, if you've cast one commander once and one twice, you'll copy this spell three times.

Rulings via Scryfall