Thanks for the responses and suggested links. Unfortunately, I've read most if not all of them. Hence, my search for more info. I guess the thing that is puzzling me most is the discrepancy in the information. As I said, one says to load as long as possible, while another says load short. For example, the Lyman's Handbook lists a maximum length of 1.169 for a 9mm, yet suggested OAL for a 115 gr. is 1.090. For 124 gr. it is 1.075. Many of the loads I've copied from experienced reloaders seem to hang around the 1.135 mark. Is there any particular reason?
And yes, I am talking 9mm, primarily from a Glock 19.
Thanks again for the responses!