From Against Calvinism:

What about other Calvinists? Do they affirm this limited atonement doctrine as Boettner did (and perhaps Calvin did not)? John Piper definitely affirms it: “He [Christ] did not die for all men in the same sense. The intention of the death of Christ for the children of God [the elect] was that it purchased far more than the rising of the sun and the opportunity to be saved . The death of Christ actually saves from All evil those for whom Christ died ‘especially.’” Sproul definitely affirms it. He prefers to call this doctrine “purposeful atonement”: “The atonement’s ultimate purpose is found in the ultimate purpose or will of God. This purpose or design does not include the entire human race. If it did, the entire human race would surely be redeemed.”