Currently, the powered up attacks on the Ironhead THammer cleave through lighter elites and specialists without discharging. This happens even on the overhead heavy attack. Triggering the discharge on single targets is extremely inconsistent.
There’s a lot of potential for this weapon to be great but its touted “feature” works to its detriment right now. I suggest swapping Heavy 1 and Heavy 3 in the attack chain and then reducing the cleave on the overhead so that it triggers the special discharge on the first target struck.