Calvin45, I'd like to thank you so much for this wonderful thread that caused such an argument between the three of us in my home this morning!!! It was between the three of us, me, myself and I! As I was reading the OP, I started to debate what the most important component was without any results, so.................decided to approach the question from a different perspective. What nmbarta wrote is what I agreed upon as the most agreeable answer, "Depends on what I intend to do with the loaded cartridge." My approach from a different perspective of what do you consider to be the least important component to the cartridge???? I would say the primer, yes I know that if it doesn't go "bang" then the best quality of the other three components really doesn't matter. But.........in my experience most any primer will get the job done as long as it goes "bang". As for powder, again in "most" instances if the powder is in the ballpark for the particular cartridge, it can be regulated to a point where in "most" cases it can be made to shoot. As for bullet if it comes out of the barrel, it is doing what it is designed to do. It may not do as well as we'd like, however it will come out of the end of the barrel and either hit paper or hit game. As for brass, well what FEENIX wrote about brass is true, however most any brass "will" work, and.......if we play with it enough in "most" circumstances we can get it to shoot pretty well. Finally after all this arguing between the three of us, I pretty much have to agree with wasskeet, "Which leg of a three-legged stool is most important?" If one is a true reloader "there's no "one" component that is more important than the other!" Based upon this, I cannot come up with a true answer for the OP, however have found this thread to be very thought provoking to say the least. And.....now it's time for another cup of morning coffee so "we" can argue and debate this issue some more.