or a stone block the cor was then calculated from the impact velocities based on the drop height and the rebound height measured cor 39 s at 125 and 180 feet second speeds were measured by firing the sphere from an air cannon at a velocity determined by the air pressure the outbound velocity generally employed is between 125 to 180 feet second the ball strikes a steel plate positioned three feet away from the point where outbound velocity is determined and rebounds through a speed monitoring device the return velocity divided by the outbound velocity is the cor fig7 is a plot of the data in the table it is a plot of the differences in cor at the three velocities determined by subtracting the cor of the base ionomer from the cor of the bi modal ionomer in each case fig8 is a plot of resilience versus impact speed of neat spheres based on blends with or without the bi modal ionomers the bi modal stiff ionomer and blends property characterization is provided in the following table fig9 is a plot of the relative cor differences at different impact velocities between the bi modal ionomer i e bmi 1 or bmi 2 containing blends and the reference ionomer blend i e ionomer 1 ionomer 2 50 50 by weight while the bi modal ionomer containing blends exhibit higher cor at higher impact velocities they exhibit comparable cor at 23 ft second to allow good putting control in combination with long drive distance bi modal ionomers of this invention achieve performance improvement over the conventional base ionomer references in the heat stability as measured by the resistance.