Stumbled on this post on Goodreads a while back and have been trying to solve it (it is not Starship Troopers, but was apparently compared to it, and there is a similar weapon in Dorsai!, but - as far as I can tell - there was never a game based on that novel):
WHEN-1950-1960's
What the story is about: I never read the book, but always wanted to. The book features a future sci-fi world where combat is between super snipers. Armies, as we think of them, cannot exist. The snipers can hit and destroy anything that is in the range of 12 or so miles. I believe there was a wargame based on the novel.
What format: Paperback