This seems to have caused a kerfuffle! "Parts of handheld guns have been found at a North Yorkshire battlefield which saw one of the bloodiest conflicts of the War of the Roses. A metal detectorist unearthed the fragments of the guns, thought to date back to the 15th Century, at the site in Towton, near Tadcaster. The find contradicts the idea that guns were only used in that period of history to attack castles." BBC News - Parts of guns found at Towton War of Roses site
I used to do a facepalm every time some student tried to imply that there were clear and distinct demarcations in history. "only used to" in that article is a prime example.
I would have thought a weapon used to attack a castle would quickly be used against a body of men in the field. Why is it such a surprise?
Vladd- Probably due to the unwieldiness and reloading times, I think. Doesn't mean it didn't happen, just that this is the first direct evidence they've found.
Perhaps I'm wrong here, but wasn't it about this time frame when European armies began to see large scale usage of firearms? To have a handful found on a battlefield from this era, doesn't seem to surprising to me.