Do you know what model of gun it goes on? If it's from an A-5 it could be worth a fair amount of money.

If no one can give you a good answer hear I can direct you to a place that can.

If it's a belgium A-5 barrel in good condition it could be worth $300 or more. I don't know about the other models.

I just looked and mine says AUTO-5 right on the side of the barrel. Mine is newer one with a jap barrel on it though. I am not sure what older ones had for markings. Like I said though, I know of a place that would most likely know for sure.

Paul