I don't see how barrels that are made to fit from one size to a smaller size can fit. If you had a 28 ga, and were going to .410, the breech end would have to be larger on the .410 set to match up to the 28 ga. breech balls. The same would be true for a 16 ga set to fit a 12 ga gun.

I think Larry had it right, you would have to send them the receiver to have them fit, then blued. Unless of course you wanted to do the job yourself. I would think the fitting would be extra.

David