Do you know where there are ANY screw-in sights for sale no matter the thread size? It had a round orange sight on it, looked exactly like a shotgun sight. It did it no justice.OK, do you know who made the barrel? Maybe they'd know. Or, sneak the gun into a hardware store's fastener aisle and try random screws until one fits. (I absolutely did not suggest that.)
Brownells. https://www.brownells.com/gun-parts/shotgun-parts/shotgun-sights-parts/?sort=NumberOfReviewsDo you know where there are ANY screw-in sights for sale no matter the thread size? It had a round orange sight on it, looked exactly like a shotgun sight. It did it no justice.
Some hardware stores have a drawer with gun screws. Check around.If you have a set of thread gauges (sorry if I have the wrong term) to see what the thread pitch is that would help.
This will keep you from issues at the hardware store
I would expect it to be a bead unless you're going to time it yourself to sit correctly.