Yes, your quite right. The gun, to be precise, Is ELECTRICALLY Driven. BUT, MECHANICALY Fired. This may sound confusing to some, but it is simple really. The Vehicles electrical system supplies Voltage to the guns 24v Motor. As the gun has a Chain in the system to drive the operating mech. The ACTUAL firing act is performed by a Mechanical Firing pin that strikes the percussion cap in the base of the round to fire it. So yes, with the safety switch set at safe the gun SHOULD not fire. BUT, there is indeed a round in the chamber if a live belt of Ammo is removed. Hence Tommo's comment of using a 'Dry Fire' Handle. This not quite quite accurate though. It's a MECHANICAL Operating Handle. IE: When fitted on the end shaft stub. You can MANUALY function cycle the Weapon. Any rounds remaing WILL be Mechanicaly fired.
The term 'Dry Fire', is more correctly applied to ANY weapon that rotates through a complete operating cycle mechanicaly.
WITHOUT using ANY live Ammo. IE: Cock, Feed, Lock, Fire, Unlock, Extract, Eject.
INERT Drill Rounds Could be utilised in 'Dry Firing'.