Change the wad seal to shell wall, like using a wad for a tapered hull in a straight wall hull and it will alter pressure. Use a wad with a shorter crush section, in place of one with a longer one and it will change pressure. Primer substitution will alter pressure, in some examples a lot. If you are really just trying to find a generic safe load, some could suggest a starting point, but the only way to know what you have is to test them.
If you are way under maximum pressure and do not care about real pressure, or real velocity, then that might be good enough. Many low pressure loads are also low velocity as well. You need to figure out what you are trying to achieve, low pressure with low velocity like 1050-1100, or low with 1200 fps or greater. And sometimes the hulls, wads, powders and primers you have on hand just will not get you want you are after so change your inputs by selecting others. Right now hulls are the easiest one to change and powders are the hardest.
