if shooting any standard caliber in a Weatherby i'd follow the SAAMI guidelines for cartridge overall length. if shooting a Weatherby caliber i would assemble it following the instructions from one of the loading manuals.....which oftentimes make mention of the idiosyncracies involved in Weatherby ammo'. Weatherby's own ammo' was shot in rifles with a longer freebore to help ease the pressures developed by their larger powder charges and to help increase velocities. standard ammo' doesn't have those pressure concerns when properly worked-up and assembled to SAAMI spec's
i would forget that the freebore exists in the rifle and load the ammo as indicated above. the Weatherby's have decent accuracy from what i've personally shot and from what i've read about. my Vanguard in .270 is a Great shooter of bullets crimped in the cannelure (Core-Lokts) or at SAAMI length (Hornady). and, because that is a 'standard' caliber, as opposed to a Weatherby creation, it may not have the longer freebore.
good shooting to you,
ss'
