Cordless Nailer Depth Adjustment Question

I recently bought a Metabo 18ga battery-operated nailer. At the deepest depth adjustment, the nails go just barely deep enough--maybe 1/32 to 1/16 beneath the surface (recently attaching 1/2" thick black walnut to pine). So it's working, but is it normal for the deeepest adjustment setting to only go that far? I'd feel more comfortable if deepest setting went a little farther, for a margin of error--it sucks when the nails remain flush with the surface.

Also: is it normal for there to be a (small) gap between firing head and wood, even on deepest setting? That's the case with this nailer.