That wasn't the hypothetical bet. We both start at 100 feet (30 paces) from one another: perfect blunderbuss range.
My first shot launches 100+ rusty nails at you with a spread pattern ten feet wide.
You are wearing a Colonial shirt and three corner hat, I am wearing a kevlar vest, helmet and ceramic ballistic plate.
I have a helicopter standing by to take me to a trauma center, you get dirty bandages, a rusty saw and a bullet to bite for medical care.
This balances 1780 vs 2003 firepower, protection and medicine. I'd take that bet.
The point is that weapons were plenty deadly in 1780, at least as deadly if not more so when you consider the total equation including medical care for wounds etc.