Found game called Duck shoot that I thought would be perfect to convert since I had a spare nintendo gun. going to make some new stickers and decals to match the game as well as 3D print new ducks shaped like the game with stickers.
The guns side by side ready for swap.
Remove all the guts from the black revolver and cut away all the loose wiring of the nintendo gun. can remove the speaker at this point as well if you do not want the gun sound effect and prefer the trigger sound of the nintendo gun.
switch and small lithium 3.7v battery as well as lithium charger that can be ordered on ebay or found at your local electronics store usually.
Since the cap wont fit I made a 3D printed version to fit in place of the lens of the nintendo gun.
I used the spare wire from the nes gun to extend the IR LED.
break off these plastic parts to help everything fit.
screw the handle back together and drill out with a 21/64 drill bit or anything you have that would fit the style usb charger you have purchased.
take the metal part from the nes gun and glue the LED to the plastic ring it comes in as well as glue it to the opening at the end of the metal.
cut off the button for the trigger and solder it to the trigger of the nes gun, colors don't matter.
desolder the original battery wires and add some extra long ones.
solder on some wires to the switch and the 2 connectors on the usb charger.
I forgot to take a photo of the wiring of this part but its just the switch red wire and the battery red positive are twisted together and soldered to the usb charger, and the negative of the battery and the negative from the gun board are twisted together and then soldered to the charger.
test video of the gun, cant pull the trigger fast like with the nintendo version of duckhunt but it works.