To increase hammer speed, the real goal is to reduce the hammer's Moment of Inertia, so
where mass is removed is important. The farther from the pivot point, the better, so it's easiest to just bob the hammer. For those wanting to keep SA capacity, though, the hammer can be skeletonized. Here's a link with some good info:
http://rugerforum.net/gunsmithing/99...ification.html