Very similar in size, but Swiss develops slightly higher velocities when the actual charges are weighed. Swiss also seems to have a higher sectional density, meaning that for a given stricken measure (volume), there will be a greater weight of Swiss in that "measure's" volume. Thus, you will get fewer "throws" using that measure per pound of powder.
Thus, if you use an old measure setting, we'll say for the jist of this post, holds 80gr. of 2F GOEX, if you used that measure full of Swiss powder, you would actually be 'throwing' 85 or
more gains of Swiss powder, likely closer to 87gr. or 88gr.