Fox Collectors

Another question about my 16 ga. Sterlingworth.
I've read something about 16 ga on 20 ga frame.
What's the story on that? How could I tell without have a 20 beside it to compare?

Thanks to all. As this is my first Fox, I'm going to try the patterning and spreader load options first. The gun in nice but probably not what a true collector would call pristine. I've shot it a few times at clays and it mounts and shoots great. But clays don't have feathers or make me cross my eye...

At the risk of creating a storm or being banned form the forum, I have a nice, well kept 16 ga Sterlingworth, circa 1927. Mod and Full. I really want to shoot as a quail/grouse gun. Am I crazy for opening the tubes to Improved and Modified? Will the value be ruined? Any suggestions on questions I sh...