To illustate how bomb/fuel load effected range, here is some data I came across on the Ju 88A.
2400kg bombload, 1221kg fuel, 1260km range, 11,900kg flying weight
1500kg bombload, 2106kg fuel, 2340km range, 12,000kg flying weight
1000kg bombload, 2609kg fuel, 2900km range, 12,100kg flying weight
500kg bombload, 3263kg fuel, 3680km range, 112,300kg flying weight