A 42: Yes.
A 40: There have been many attempts to homebrew realistic gun rules. Iron Kingdoms from Privateer Press has a decent system. There's a great system, for all tech levels and types of guns, but I just spent a good ten minutes trying to find it and I have no luck. Only clue is that it was used in a GitP play by post game set in the carribean and includes rules for all types of early guns (matchlock up to flintlock/wheellock/late renaissance).