I'm not at all conversant as to how strong a conventional double is, for the English side of things if you required for more energy a bigger bore in larger sizes with heavy projectiles at 2000fps or there abouts with huge cases the size of cigars to keep the pressure down.
Unlike the Weatherby which operates at a far higher pressure, the rifle that contains it must be incredibly strong if it is of the conventional type!
When comparing strengths & double rifles, yes Bailey Bradshaw's design would easy contain such a monster!
https://bradshawgunandrifle.com/rising-block-double-rifle