Yes, that has to be the books. The dart shooters are called spetzdods and the robes are of a special material that protects them from heat, cold and water.
They are part of a very good (overall, some books are better than others) series called Matador. Books are:
The Man Who Never Missed
The Machiavelli Interface
The Omega Cage
The 97th Step
The Albino Knife
Good quick reads. I have all of them up for trade over on SF-Books.com , a book trading site for SF&F. Come check us out and if you decide to join up, tell them spacecat sent you!
And it looks like there is also a new book out in '05 called The Musashi Flex.
I'm trading SF&F books at
Tell'em spacecat sent you!