Stephen Hunter does real well in that area. I've seen one error but that could have occurred during printing. The novels I've read of his: G-Man, Hot Springs, Pale Horse Coming, and a couple of others. Currently on Havana and have The Third Bullet, which is about the JFK assassination, on deck. His novels are fiction and not always historically correct...in one instance his protagonist kills a mafia figure, but in real life the mobster died 30 years later of natural causes. But he makes that clear in the acknowledgements at the end of the book.
That's because he's is a hoplophile himself...as I recall from reading about Hunter years ago, he not only is seriously into precision shooting, but also competed, at least in amateur shooting sports.
Greg