Yes, they actually did have an advantage - they were much quicker to load.
I wish folks could find some crossbows with detachable cranquins, just so they can see how long the danged thing takes to load. No to mention that it is actually fairly hard work to get the bugger cranked up.
Even a hand cannon will get in at least three shots to every two with an arbalest. Four with someone who knows what they are doing.
Don't get me wrong - I would still rather have a crossbow than a handgonne, but the matchlock was really where the deathknell of the crossbow began as far as war was concerned. For hunting, the crossbow remains a better choice, at least until the wheellock (though wheellocks were much more complex and expensive), the snapchance and the flintlock made guns cheaper as well as faster than the crossbow.
My own favorite period for gaming is c. 17th century. Printing presses, religious turmoil, the dissemination of improved mining technologies, and, yes, decent guns....
The Auld Grump, oh, cursed be the locksmith, that made me old gun,
For I've shot my own true love, in the rue of a swan.
She had her apron wrapped around her, and I took her for a swan.
But alas and alack, it was she, Polly Vaughn....
Actually, that's why I specified it should be a duel. I might be mistaken, but my impression of ye olden duels was that if the first volley missed, there were extra loaded pistols on hand for them to try a second round, rather than becoming a contest of reload speed.
IMO, it would be insanity to attempt to reload a musket or similar firearm during a typical D&D encounter (at least if one uses realistic reload speeds). You'd likely be cut down before you could finish. That's why I wanted to exclude reload speed from the equation.
I was referring merely to the deadliness of the two weapons, under circumstances where reload speed is negligible. I presume that a crossbow bolt has a similar effectiveness to a musket ball for inflicting injury and death?
Regardless, thanks for the informative response!