Very new to DDO (about a month reguardless join date)
Have now done Chamber of Raiyum 11 times without getting a rune arm drop.
Cult of the six took 2 tries.
Seal of Shan-toKor took 7 tries.
Assault on Splinterskull took 9.
Just unlucky?
The drop rate get worse at higher levels?
Any of the rune arms have a single shot at a drop and if not the first pass your screwed?
Have yet to see any posts on this in specialists...maybe looking in wrong section?