We're getting away from Hatari's original question here, but what the heck.

I have shot a couple or three buffalo on the point of the shoulder with soft-nose bullets from .400 to .577, and never had one fail to get through into the vitals. Typically, they will pull-up in the off-shoulder after smashing it if directly side-on, or pull-up under the hide or at least at the rib-cage if it misses the 2nd shoulder. The qualifier here is that I always use Woodleighs on buffalo, and velocities are 2000 to 2300 fps.

I would never consider a solid for the first shot at a buffalo bull. Bonded-core softs at modest velocity will deliver all the penetration you could ever need. Which brings us back to the Weatherby angle. Driving any bullet too fast, solid or soft, will potentially jeopardize penetration. How fast is too fast? Depends on bullet design and construction of course, but Weatherby velocities are generally too fast for normal 'premium' hunting bullets IMHO. They demand specialist bullets designed for high velocity, which is where homogenous construction with nose cavities or large meplats come into their own.

Just my thoughts, gentlemen....