Having trouble with this game saving high scores...
Hiscore plugin not working in Tailgunner for me, either, but I haven't dug into it.
https://docs.mamedev.org/plugins/hiscore.html- Running MAME from command line with -verbose might help you narrow down what is and is not working.
If you can't get the plugin working, save states
are working for this game.
- Make a simple "tailg.ini" file like this that enables autosave.
#
# CORE STATE/PLAYBACK OPTIONS
#
autosave 1
- It will throw an error the first time you run it with the new .ini because it didn't autosave last time you exited the game.
- Second time you run it, it should work.

- AFAIK the only downside to this approach is the momentary "State successfully loaded" popup window when you launch the game.
Scott