There were a number of different chamberings offered for the 219, including .30-30, .22 Hornet, 12 gauge, and I believe 20 gauge.
There are also reports of .32-20 and .25-20 barrels having been offered, but no one I know has ever seen one.
The gun was made in two models, both called the .219. The earlier ones I believe had an extractor, and the later ones had an auto ejector.
The newer barrels will work on the older guns, but not in reverse.
At least I think I have all that correct.