Stockler and Beck Punisher

"The Punisher deals a huge amount of damage at all ranges, but its small clip doesn't make it the ideal candidate for taking out vehicles. Expect plenty of recoil when firing this beast of a gun."

The Stockler and Beck Punisher is clearly based on the IMI Desert Eagle.

Trivia
In the Capelli Family intro cutscene, one of the Capelli Family soldiers can be seen wielding a Stockler and Beck Punisher; however, they are never seen using it at any other point in time.