If they don't agree with you, then they know nothing, right?

This is what I mean by being arrogant. You always come at these posts like you are the only one with any knowledge. A lot of us, have been at this a long time too. You can say what you want about it all, but now you are the one who is giving bad advice to newbies who may be reading this thread. Bearing surface length, and bullet composition have just as much to do with pressure as depth of seating. All three are equally important. Pressure doesn't peak until the bullet has engaged the rifling, plain and simple. Sure there is some presuure upon ignition, but it hasn't reach maximum until the bullet is being held back by the rifling.