Do I have a Brass or Chamber problem?

[Rocky Raab]

That amount of case expansion should raise red flags. Start loads shouldn't result in ANY base expansion, so there's certainly something wrong going on here.

Is this new brass, once-fired or "tired"?

Standard primers or mags?

And a few gun questions: Is this a recent Contender frame, or an older one? You say it's a Custom House barrel, but is that the T/C Custom House or somewhere else, and is the barrel unaltered since then? (I'm wondering if it was originally a .22LR from the custom house, for example.)