Do Corked Bats Make the Baseball Travel Further?

No, says Lloyd Smith (h/t Mark Thoma):

Some baseball superstitions are accepted as cold, hard truth. But in the world of physics, the most accepted verities are subject to experimentation. A corked bat hits the ball further? Not in Lloyd Smith's lab.
Baseballs today are livelier than in the past? See above.
Storing balls in a humidor can curb home run production? We'll grant you that one, but only because Smith has fired the balls through a cannon and measured their bounciness as they hit a bat.
Smith, an associate professor of in Washington State University's School of Mechanical and Materials Engineering, tested all three premises his Sports Science Laboratory on Pullman campus.
"I've got the cool machine that can do the tests," says Smith. Working with colleagues from the University of Illinois and Kettering University, his findings are in this month's American Journal of Physics article, "Corked Bats, Juiced Balls, and Humidors: The Physics of Cheating in Baseball."
The juiced-bat question arose in earnest in 2003 when Chicago Cubs slugger Sammy Sosa was caught using a bat that was illegally drilled out and stuffed with cork. The researchers first took a 34-inch wooden bat and repeatedly measured the speed at which a ball bounced off it when fired from a cannon at the combined speed of a thrown ball and swung bat. They then hollowed out the barrel of the bat, stuffed it with bits of cork and fired the ball at it again.
If anything, they found, a ball came off a corked bat more slowly than a regular bat.
However, the authors acknowledge that batters might cork bats to make them lighter, improving their ability to "get around" on the ball faster and make more solid contact. But fully addressing that issue would require player interviews, acknowledges Smith.
"They're not going to want to talk to us about this," he says.
The issue of juiced balls emerged in 2000, when the first two months of the major league baseball season saw substantially more home runs than the same time the previous year. In 2004, the researchers compared contemporary balls with a batch of late-'70s balls provided by the family of former Oakland A's owner Charlie Finley. They fired them at both a steel plate and a bat at speeds of 60, 90 and 120 mph.
They found the balls' coefficients of restitution—their ability to bounce—were nearly identical.
In retrospect, Smith speculates that it may have been the players, not the balls, that were juiced.

The corked bat theory never really made much sense to me, other than lightening the bat, while keeping the barrel diameter.