Clamping apparatus extending through a passageway formed in the frame of a game ball racket for applying non-uniform clamping pressure to a length of a game ball string adjacent an end thereof to clamp the length of string to the game ball racket frame, the non-uniform clamping pressure is minimum at the forward or pulled end of the clamped length of string where the tensile stress produced in the clamped length of string due to stringing and play is maximum and which non-uniform clamping pressure increases to a maximum at the free or rearward end of the clamped length of string where the tensile stress therein is minimum; the tendency of the clamped length of string to rupture at the forward or pulled end of the clamped length of string where the tensile stress is maximum is reduced because the non-uniform clamping pressure applied by the clamping apparatus of the present invention is minimum at this critical point.