The Beretta 93R ("Raffica") was developed in the 1970s by Beretta engineer Paolo Parola at the request of Italian military special forces. It took the basic Beretta 92 pistol design and added a well-thought-out burst mechanism under the right-side grip panel. It does not have a plain full-auto setting, but only semiauto and 3-round burst. To help keep the gun controllable, it has a heavier slide to reduce cyclic rate, a detachable shoulder stock, and a folding front grip to help control the muzzle. It uses extended 20-round magazines and is actually remarkably controllable (or so I am told; I have not had a chance to shoot one myself).

For a look at a 93R on the range, I suggest this video from James Reeves on TFBTV:
https://www.youtube.com/watch?v=4M_1r3rHiFk

Many thanks to the Royal Armouries for allowing me to film and disassemble this very famous machine pistol! The NFC collection there - perhaps the best military small arms collection in Western Europe - is available by appointment to researchers:
https://royalarmouries.org/research/national-firearms-centre/

You can browse the various Armouries collections online here:
https://royalarmouries.org/collection/