Hevi-Shot is now a brand, not just one type shot. The Classic is safe to shoot in anything. Soft like lead. The Hevi-Shot Duck, Goose, and the various mixes like Hevi Metal I would not put through the Browning or the Marlin, period. Depending on the vintage of the Ithaca, it may be okay for shot sizes like #2 or smaller. The wads now are so much better than they were you can push the envelope beyond what you once could, but a bulged barrel in the choke area cannot be "unbulged".
Look at Kent Impact tungsten matrix. Safe in anything, and very, very good, but expensive. But then so is Hevi-Shot. I think it's worth it.
