mach 1

Actually the USGA has a limit of the reactive speed of a golf ball, for the preservation of the game. ( one of several key elements of ball design ). The reactive speed is the speed at which the ball will rebound form the surface of the club, after it has been compressed by the club. The ball 'reacts' to being compressed. The amount of reaction is proportional to the amount of compression achieved, to the physical limit of distortion of the ball. The 'speed' in flight will rapidly diminish as the ball and its dimples interact with the air. Deceleration and distance are both affected by humidity, temperature, and altitude.

I once made one go 600 mph. over the ground! I should mention it was in the 727 I was flying. Not the answer you were looking for.

The world record is 205, golf is the fastest projectile sport. +3

Apparently golf balls go 150-200 mph. Fast enough to break a window but not a roof.

A brief web search turned up 115 mph and 180 mph, which are not too close to each other.

Two hundred yards in about 5 seconds.

There was a few in the trunk when little Ec hit 130 in the his brother's Mustang (many moons ago yo...:)