Sounds like a nice gun at a very good price.

Those bores are tight for a 12 - I had one that had a barrel at .719 that a plastic wad got stuck in that could have easily blown the barrel if the guide didn't say that load sounded weird. Maybe that is why someone was shooting 28 gauge tubes?

I have never shot anything but plastic wad factory loads, but maybe a fiber wad would be better suited to those bores?