I found some 250gr Remington RN bullets in my stash. They are .455" which feel like a better fit in these chambers.
They don't bind, but they don't flop around either. The reviews say they're soft, just like HawkI said they'd be.
I'll stop using the Titegroup and go with good ol' Unique.

I'll post the results in a couple of days. Thanks again guys. I feel like I'm on the right track here.
It's a good feeling.