I've loaded 9mm anywhere from 1.060 to 1.135, I think the SAAMI max COL is 1.169 for 9mm. (Just going off memory here) As shone above different bullets have different shapes and different over all dimensions. (Some bullets are longer than others even though they are 9mm) You can use the published load data and start out at the lower end and work your way up. But as you shorten you COL, using the same powder charge, the pressures go up. (That's assuming you are using the same bullet each time) Look over at the Hodgdon's web site and they have load data for Titegroup.