Anybody know why in the later renaissance lists they dropped the range for muskets & arquebusses to 18"
(handguns in the book are 24")

I don't recall off hand, but it may be to reflect ammunition, or rate of fire or (lack of) effect at long range

Of course I type all this and then recall that historically, (I think I have this right) the two sides would tend to wait until they were quite close to one another before engaging in a fire fight