Echo Storm

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.

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.

If the copied artifact has {X} in its mana cost, X is considered to be 0.

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.

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.

If your commander was countered, that time you cast it still counts.

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.