The Centurion Action X is a nickname of the official "Centurion Mantletless Turret" design. The Centurion Mantletless Turret was a project to create a new, heavily sloped turret design for the Centurion as a form of upgrade, taking inspiration from the Chieftain's turret design that also features no gun mantlet. The Centurion Mantletless Turret did not end up seeing widespread usage, with only one surviving example existing at the Bovington Tank Museum.

The Centurion Action X was introduced in Update 1.93 "Shark Attack" and looks similar to the FV4202, which also has new gun mantlet-less turret. There are some marked differences though, such as the thicker frontal glacis (although less sloped than FV4202), some different contours in the turret slopes, and slightly better mobility due to the stronger engine. Otherwise, the Action X plays similarly to other 20-pdr equipped Centurion types, with balanced mobility and firepower and a new, more sloped turret that can help the tank hold its own in a British Post-war line-up. In the right hands can prove to be a menace on the battlefield. It will be appreciated by aspiring tankers and veterans of the British tanks both, while also giving a little preview of what the later ranks have got to offer.