@FRAQATTAQ said in Light gun does not work for most games:
Guide used: Wagner tech talk
Could you provide a link to the guide, please?
Emulator: emulation station / retropie / mame
Emulation Station and Retropie are not emulators, and Retropie supports a number of different MAME versions. See here for a list. Which one did you try?
The default MAME of the official Retropie image is lr-mame2003 which uses the romset of MAME 0.78. You can see the emulator used (and change it) in the Runcommand Launch Menu.
You'll need the right romset for your MAME version, other romset will probably fail or cause problems. See lArcade and Validating, Rebuilding, and Filtering ROM Collections for more information about that.