Yes, the more jump, the lower the start pressure. Think of it this way. If it is jammed into rifling it takes a lot more pressure to start that bullet into the rifling because there is no momentum. The longer the jump, the more momentum and lower start pressure. If you want to work at .015 off the rifling, that's all fine but you will need to find an accuracy node for that OAL with a lighter load. You also need to consider temperature. A load that is on the upper end of pressure but safe at 30*F will be way overpressure at say 70*. Many guys, me included, pick our bullet and powder, start loading at a known safe level and work up in .3 or .5 gr increments depending on case capacity until we see pressure and then back off. Do this at hot temperatures if you could be shooting in hot conditions and you will be fine at colder temps but developing a hot load in cold temps and then shooting in hot weather is going to be over pressure.