12GaFH, 73 cal IS a rifle...a very BIG rifle...20Ga IS a .620 cal... Ed Hubel has a .585 cal that will punify the Snider...
...it is a stub barreled object de'Art. They are ALL rifles, just not FACTORY available. Ed also has 10Ga and 8Ga's on the NEF frame.
Those are mind blowing thing's Ed is doing with the NEF frame...SAFELY.
Check out Accurate Arms, Big Bore, 12GaFH thread.
Some require cubic dollars but most...except for the dies and brass costs...are relatively inexpensive to do...the cost of the NEF, a rechamber...a muzzle brake...much less than you'd expect.
I'd much rather have an 8GA if facing a PO'ed bear, buff or T-Rex...one shot and it will roll the beasty over, skin it, cut it into steaks and BBQ it...all you need is a fork, plate and chair....Hahahahahahaha
Luck