I've had some GGs that did not "snap" into focus because they were coarsely ground for a better aerial view.
The coarse grind shows its shortcomings when a high-powered loupe is used (8x or higher).
Since I use a 10x loupe, I had my existing Gas ground even finer so that the grain was very minuscule.
This gave me a darker GG, i.e., I couldn't see much in the corners from 18 inches away, but focusing with my loupe was great.