I guess roughly 47fps..
But why would you go with such a short barrel for such a large cartridge?
Your gonna get a great big ole high pressure/high flow fireball at the muzzle, which don't contribute to clean bullet release.
thinking of buying a savage 11 lightweight hunter in 260 rem. also thinking about buying the lightweight hunter and making it into a 7WSM with about the same contour barrel fluted and 24" long. mountain carry rifle i guess.