It's not entirely clear why the Russians might be interested in creating their own version of the AC-130 now, either. The general concept of converting cargo planes into armed gunships has been around for more than 50 years now, but the U.S. Air Force has remained the largest and longest operator of such planes.
Today, that service uses them almost exclusively to support special operations forces and at night, where they can also use their powerful sensor suites to also perform persistent intelligence, surveillance, and reconnaissance (ISR) and armed overwatch missions. Russian special operations units, commonly known as Spetznaz, have been steadily taking some inspiration from their Western counterparts and have been increasingly employed overseas in various limited conflicts, especially in Syria, all of which might have prompted demands for a capability akin to an AC-130.
The general principle behind the side-firing gunship is, by now, well-established and combat-proven. A plane with guns sticking out one side and flying in a tight circle over a particular target can provide precise fire even without the aid of modern sensors and combat-aided stabilization and targeting systems. To this day, variants of the AC-130 employ simple holographic sightsmeant for small arms and light weapons mounted facing out one of the side windows in the cockpit to help the pilot keep the aircraft stable in its orbit around the target area.
In addition, though automatic cannons fire high-explosive shells, they also simply offer a smaller blast radius than traditional bombs and missiles, making them well suited to engaging targets that may be dangerously close to friendly forces. The U.S. Air Force had been working to develop gunships that would almost exclusively employ precision-guided munitions, rather than guns, but has steadily reversed course for this reason.