hi i just wanted to ask if the felling quiality does ignore unnatural toughness of a enemy if this one has true grit.

for example the acolyte John it a chaos space marine with a weapon with felling 4, the space marine got enough damage to be at -6, but he has true grit, so if he has unnatural toughness 4 and toughness 40, will he be at -1??, or at -2??

thanks in advance

PD: and what happen if instead of ussing a weapon with felling, the acolyte uses a psiquick power like haemorrhage?? (wich ignore toughness)

Felling does pierce Unnatural Toughness for the purpose of True Grit. This wasn't stated explicitly in Dark Heresy 2E, but it was in Only War and the rules used (Felling, Unnatural Toughness, True Grit) are nearly word-for-word identical.

Question: How does the Felling Weapon Quality (page 169 of the Only War Core Rulebook) interact with the True Grit Talent (page 152 of the Only War Core Rulebook)?

Answer: A stated on page 169, the Felling Quality’s “reduction occurs for calculating Damage only and does not persist.” This includes the calculation of Critical Damage (which the True Grit Talent reduces). Thus, an attack with the Felling Quality decreases the target’s Unnatural Toughness for the purposes of the Critical Damage reduction the True Grit Talent applies.

Edit: On the subject of effects which bypass damage reduction, FFG hasn't set an explicit precedent. But I would suspect that by the question/answer above, such would also bypass True Grit.