There is an ammo cache at the end of the level, at a bridge.Do not destroy artillery or anything else until after they're down.Take out field guns first, before anything else can take them out.There are a few ways that we're going to combat these issues. Many players have also reported missing field guns, or guns that have glitched out of the terrain. This means that any field guns that blow up from artillery or friendly tanks will then void the codex. You need to destroy them personally with the tank. This is a very important note about the current codex challenge, so read carefully: OVER THE TOP Objective: Capture Piccadilly Mill Challenge: Destroy all field guns in Over The Top The Tactics - Tank Warfare in World War I.