Nucleon Shock Cannons fire what appears to be a fully charge Plasma cannon bolt. They come in turret mode, and un-attached mode. Destroyers use a rapid fire version of them.
Despite the facts that they more resemble real world flak cannons, and that they appear to fire bolts of plasma, this weapon is classified as a missile launcher.
In the first chapter of Fall of Cybertron campaign, Megatron picks up what appears to be a Nucleon shock cannon. However, unlike in War for Cybertron, where the explosion radius is huge, Bumblebee only appears to get some body damage and looks as if he was dying, unlike the massive disintegration in War for Cybertron.