A really Serious big game rifle also uses paper ctgs., as Dan will attest. Mine, a caplock, was capable of being re-loaded, aimed and fired in 8 seconds. Yes- 8 seconds after the recoil of the first and a well aimed second shot is fired. The English gun design allows this. A longrifle or Hawken design is considerably slower to align.
A fast second shot was important (I thought) with my first moose with this rifle. Just at dusk, my first moose with the .69 appeared down the draw. The temperature -35 & the shot taken at about 100 yards, except the first ball, a pure lead, cloth patched one, travelled through 50 yards of willow tips before striking the moose boomfttttttttttttttttttttttttttttttwhock! The moose's butt hit the ground and he shook his head back and forth as I recoved from recoil and started loading anew.
Just as he gained his feet, and turned to depart, the second shot ripped out though from the opposite side of initial impact, hitting fewer willows fttttwhock. He hit the ground again and stayed - what a wonderous feeling, with a new rifle to see such smashing power. The sound at impact was amazing.
The first ball, hit 12" left of the aiming point, probably due to hitting all that wood on the way to the moose & only had enough jam to smash the on-side leg bone- almost 4" in diameter, then stop against the ribs without penetraing into the cavity or hitting anything vital. That was enough to stop him momentarily only. How far could he go after that is anyone's guess. Hit hard but hardly fatal that day, I could have lost him, but a quick second shot anchored him before he could fully recover that first 484gr. smack. This is why I like large bores - they have smashing power. The second ball of WW metal, smashed 2 ribs on impact, bored a 4" diameter cookie cutter-type hole through both lungs and smashed through the blade low where it's thickest, to stop against the hide on the offside. I was impressed. The moose was too.
So - yes - even with a muzzlelaoder, I believe in a 'relatively quick' second shot. A lot can happen in 8 seconds - with a lesser rifle, he'd have been lost or at least, a follow up the next day would have found him in a bed, still alive, probably.