I wrote a LabVIEW VI to measure ball speed using two IR sensors spaced a few feet apart detect when a ball passes by. The NI USB 6009 interface measures the analog voltge from each sensor (using a pull up resistor in series with the signal). A LabVIEW VI is used to determine the time difference between the leading edge of the signal from each IR sensor.
The Block Diagram of the VI is not elegant (and I'm sure there are cleaner ways to code the VI) but the front panel looks pretty clean.
Front Panel View of the LabVIEW Speedometer VI
I'd be happy to send the VI to anyone that would like to give it a try with their system & shooter - just drop me a note and I'll email the VI.