The sd is 18.77 - that assumes you're interested (as you should be) in the sd of the entire population of velocities, of which your 12 data points represent a sample. Average deviation, which is what I think you mean by average spread is 16.01 - that's the average of the absolute values of the difference of each shot from the mean (you didn't ask, but the mean [average] is 2041.4). The extreme spread is simply the highest value (2069) minus the lowest value (2017) = 52.
