I'm a collector, and hunter with Nitro express double rifles, and I own several from 8mm to 577NE 3", but the worse thing I ever shot was a 100 cal Rampart rifle that weighed almost 30 lbs, and was 5 ft long over all. The one inch bore bullet weighs 1050 grs and is pushed by 300 grs of black powder . You certainly don't have to ask anyone if the rifle went off when you pull the trigger, and I only fired it once ! Absolutely no desire to fire it again!
These rifles were used back in the wooden sail ship days, to knock off the helmsman from long range, fired from the ramparts of the forts at the mouth of bays. The ships attacking didn't sail straight in, but came parallel to the shore, and at the last minute would turn into the bay mouth. While the ship was in a steep turn, the rifleman on the rampart would fire on the helmsman, so when he released the wheel, the ship would suddenlu stall, and almost stop, giveing the cannoniers a sitting shot at the invader with a battery of cannon! Needless to say, this rifle was fired only once per attack, luckily for the sniper!
That thing made my 577NE double feel like a 22 lr by comparison! About the smallest thing I shoot today, is a little 8.3 lb Merkel 140E 9.3X74R double rifle.