The Weatherby Vanguard is a Howa 1500 and if it is a short action rifle you must use a two piece Remington 700 base. If it is a long action I believe the one piece will also fit.

However I absolutely hate a one piece base if it isn't needed (Semi autos and levers). Not only do you have only three 6-48 screws instead of four absorbing all of the recoil from the rifle and keeping the scope zeroed you have a big piece of steel that gets in the way of loading. I also think a one piece base ruins the asthetics of a bolt action rifle as well.