Heres a calculation, for a 100 stacker you need a 203 dispensers, so 203 tnt for sand stacking + 8 for one shot, thats 211 and if you have to slabbust in same shot thats 68 more thats totall of 279 tnt for 1 wall, and you go like thru 40 walls and you cant even open chests, that sucks, and good...