That's the sound of the Butcher's Walther, and you hear it often in FIRE BOMB, written by James Dockery using the name Stuart Jason. Dockery wrote the first nine Butcher novels, but had started using the Jason pseudonym as early as 1969 on a series of novels set on a Southern plantation.
FIRE BOMB, published by Pinnacle in 1973, sends the Butcher to Baghdad to discover and destroy a pipeline of dope making its way to the United States. Traveling with Anna Helm, a Las Vegas casino cashier in a bad way after clashing with her mobster boss, the Butcher does finally find the drugs' source, but stumbles upon a crisis even more important. A mysterious masked Arab calling himself Ibn Wahid has stolen five U-2s and plans to use them to drop atomic bombs on Russia, thus starting World War III.
Dockery does a nice job keeping the body count high, even if his final twist is a tad farfetched. Like the best writers, he's able to describe the Iraqi setting quickly and clearly to let the reader picture it, while not getting bogged down in extraneous details.
FIRE BOMB also continues the Butcher tradition of pitting the hero against a never-ending series of grotesque hitmen with ridiculous monikers (how does Rum Dum LaGoona grab ya?) out to nab the $250,000 bounty on his head.