“Oh, c’mon. Wouldn’t you just LOVE to hunt a T-Rex or Triceratops with a 20mm ATR or .50 BMG rifle? Talk about a boon for big game hunters...
It ain’t the T-Rex that would bother me - its the little raptor-type critters that attack in packs...”
Bring back the 20mm Lahti!
for your second problem, I’d suggest the 10ga. 3-1/2” magnum BELT-FED automatic shotgun... (which is what I tell my daughters I’ll use on any boys who show up looking for them...)
Dunno of any belt fed shotguns. Need a link.
I’m kinda old fashion, though. I like the Winchester 1887 lever action...