[pasbesoin]

Bad form, perhaps, to keep responding to myself. But, where I used the word "shooters", consider also hunters. A real need to know trajectory under varying circumstances. Also a strong interest in location and orientation, where a smartphone GPS and onscreen mapping would be quite useful. Mapping of various sorts, including not just satellite and topo, but even property ownership; if you are hunting on private land or need to avoid straying onto same, it is useful -- perhaps critical -- to know the boundaries.

This isn't all in place, yet, in a convenient fashion. But I can imagine it falling into place.

You need your phone with you, anyway, if nothing else then for use in case of accident, injury, getting lost, vehicle failure, etc. If it can do all these other things for you, well, that's the cat's meow.

If my imagination bears any resemblance to what evolves, it would seem to me to be a pretty decent market to sell into.