The left is one of the prototypes, and the right one of the early production. These long slides (which I like) must have been a carry over from military and 600 yd. + shooting. Of course the early days bullets of heavier weight were in use and I think this must have been the bulk of the influence. As bullets of lighter weight were used that much elevation is not needed. (sure makes for a bad head position). These sights look great on the early rifles!