Check with Mann's , there a small place in central IL. They have some 3200 barrels, I found them on Gun Broker.
What gauge. are you looking for? I saw that you wanted 28 inch barrels, but didn't see a specific gauge.
What about getting a Mann barrel then send it to Briley and get it tubed? After you get it fitted of course.
As far as I know Remington never made anything but 12 ga. in the 3200. You would have to get a tube set of one brand or another.
Remington did offer a 3200 4 barrel set. After that model was discontinued, a few 3 barrel sets (20,28 &410) were offered for sale. I believe they were sold as a set only--not by individual gauge. regards Bob S
I have the 4 barrel set with bad 28ga barrel. I have seen these barrels for sale just not when I need one.