Official PvP Server, theres a Clan (Dying Breed) that has a map room set up inside of a building. They have the same building structure on every maproom. They go slight up, where stairs have two steps showing and build a foundation. I believe they have 3 squares, 1 triangle, 3 squares, 3 triangles and repeated until a circle structure is built.
I used 20 bombs and 100 arrows trying to open the door. I tried placement close, far, shot at the top of the structure. Nothing happened. I checked server time and we were open to destruction. I was at 709pm one day, did it another day at 910pm, then another day at 11pm. The first time I didnt bring a repair hammer, all the other times I did. No damage on any of the structures. I tried three different structures and nothing.
I was trying to gain access to their map rooms to use them. Thats all I wanted. I looked it up and it says there are ways to build that stop bombs from damaging. It also says theres an exploit in servers that can prevent damage from others. Its an official PvP Server with clear times listed