Recent upload on our server was this awesome Sinden Light gun image based on the Harry Dog v8 Sinden build – but fully loaded with 200 Lightgun games across Arcade, 3DO, NES, SNES, SMS, Genesis, SegaCD, Dreamcast, Naomi, Atomiswave, hypseus-singe and PSX (including all bios)
Its worth noting that to boot this image, you need the HDMI lead plugged into the HDMI socket NEXT to the power socket. This Image runs stock clock settings; if you have a good cooling solution for your Rpi4 there are recommended OC settings commented out – OC at your OWN RISK
Other lightguns would need to be configured as required. If using other mouse devices such as a trackball or spinner, you may need to change the mouse index settings.