CALLAWAY BIG BERTHA B21 DRIVER  Callaway have taken a new approach to driver distance with the release of the Big Bertha B21. Previously drivers that have been created to reduce side spin and help keep the ball straight have done so at the expense of distance. The B21 promises to eliminate slicing whilst keeping ball speeds and overall distances high.   With an extremely low and forward centre of gravity the B21 driver is one of the lowest spinning drivers on the market and lower overall spin also means less curve on shots. Historically, a golfer has had to create above average swing speeds to get the most out of forward cg, low spin driver heads as failure to create enough speed would see the ball fall out of the air much too quickly. ...