An alternative to opening up an action is to lengthen it. Take two identical actions, such as M98s or M1917s, cut them in two about 1/2" off center, and weld them back together matching the long pieces together, and the short pieces together. This results in a long "magnum" action, and a short "Kurtz" action with one fell swoop. Frank de Haas alludes to this in his book Bolt Action Rifles.