The mauler

The Type-52 Mauler is an unusual weapon exclusively used by the Jiralhanae as a handgun, although human military experts have classified it as more of a handheld shotgun then anything else. The Mauler is based on the Jiralhanae's Pre-Covenant technology, meaning it has been in use since they first learned how to create a firearm. It is an unusual design more comparable to a revolver than a shotgun with regards to it's loading style; it's hand grip is somewhat reminiscent of the Sangheili Energy Sword. The magazine holds 5 shells of an unknown type of ammunition. The magazine appears to constantly keep the shell at a consistent superheated temperature. The mauler is mainly employed by Jiralhanae security forces, and is not seen by Humans until the Battle of Earth. The weapon also appears to be gas operated as a type of gas can be seen exiting the weapon when fired. Like all Jiralhanae weapons the Mauler is equipped with a small blade underneath, making it a formidable melee weapon.I have got this info from halopedia.com