Haha, relatively high, you can say that again. 9mm runs TWICE the max allowable peak pressure than .45 ACP per SAAMI standards.

And the Star Super B was beautifully showcased in the movie Pulp Fiction. Many gun cranks thought it was a typical Hollywood detail gaffe when Julius said "...and Mr. 9mm here..." because his pistol looked for all the world like a bright nickel 1911 which simply must be a by God .45! But nope, it was a Star.