Aside from that 1 attack is a pretty bad sample size. You need like hundreds of attacks on different armoured mobs...
I couldn't agree more...one attack isn't just a pretty bad sample size, it's dismal to the point of worthlessness. But, for my purposes, I respectfully submit that I didn't need a sample size, rather just a single example of damage that was below the lower limit of the range my character was capable of. If you accepted my premise that the lowest damage my character should have done in that situation was 38-39, then 34 works just fine to demonstrate something is wrong...and I felt it likely that that something was Bully (rather than the Bow skill or Ranged Power Stance).
But, as I inquired and you pointed out, Bully being broken isn't the only option. The other option is that there is a hidden factor(s) not shown in D:OS' too-lean damage log. In this case, per your example, physical resistance (piercing) is the most logical culprit.
So, unless anyone comes forward to positively validate that Bully is indeed broken, I'll consider the matter closed and take solace in your assurance that Bully was not a talent point ill spent.
I'll conclude by saying that it seems to me that turn-based games like D:OS are particularly susceptible to these kinds of doubts. You have so much control over combat -- unquestionably a huge part of turned-based combat's appeal -- that properly working mechanics are essential, a kind of unspoken pact of trust between the developer and gamer-customer (aka it needs to work as promised). Consequently, the value of transparency is greatly elevated in these games, which is to say it'd be great to have a properly detailed combat log.
Thanks for your thoughtful input,
Geezer