Influence: Page first, followed by Keith. Page was directly responsible for the .243, the 7mm magnum, and was one of the prime movers behind benchrest shooting, which has been a huge influence on guns. Keith was the daddy of the .44 magnum, and a constant experimenter. Whelen was hugely respect by the gun industry, but I don't recall that he was an advocate for anything in particular, and O'Connor simply reported on what was there. He made the .270, but he wasn't responsible for it.