I can't answer for the Weatherbys, but the Tikkas, at least in the WSMs, do have long thoats. From what I have been told, the Tikka WSMs loose about 200fps because of their longer throats. Not only have I read this in one of the magazines (it was a comparison between a Savage and a Tikka, and the Tikka in .270WSM was 200fps slower than the Savage model), but also members with chronys have also confirmed this.
If anyone out there can help me out....please jump in.
Zachary