As of today, April 30, a specific version of Callaway's Big Bertha 460 driver will be placed on the USGA list of non-conforming clubs. Just like the recalled Nike Sumo², the problem is the spring-like effect, which went over the characteristic time limit correlating to the USGA's coefficient of restitution limit of 0.830.
The guilty party is the right-handed version of the Big Bertha 460 13° HT model. It's distinguished by a raised dash in the letter "B" in the word "Big" on the sole of the driver.
Callaway has asked its retailers for information on anyone purchasing this specific model as a prelude to replacing them. It is not thought a substantial number had already been purchased. There's no word yet on the Callaway web site as to the replacement procedure. Callaway said the issue involved a manufacturing problem with only one its suppliers and resulted in a small percentage of the shipments already made.
E. Michael Johnson and Mike Stachura - a.k.a. "Bomb and Gouge" - broke the story in GolfWorld on Friday.