Guardian Weapons vs High Toughness

[Spear of Achilles]

Guardian guns are not sniper weapons but auto wound on 6's....does this affect monsters that are immune to their damage due to high toughness? S4 cannot wound T8, but a Sniper weapon is S ---.

[Dam13n]

"Bladestorm:  When a weapon with this special rule rolls a 6 to wound, the target is wounded automatically and the wound is resolved at AP2" - Eldar Codex page 63.

 

It works like rending, with the exception that it doesn't affect vehicles (doesn't grant +D3 armour penetration)

 

So yes, a bladestorm weapon wounds anything on a roll of 6 regardless of toughness.