Harlequin shadow seer impossible to snipe

As I read it a sniper does a mortal wound on a 6+ to wound (this goes for a lot of other weapons too). The shield from harm substrate one from the to wound roll. If the sniper got +1 to wound from a character he would do mortal wounds on a 5+. The same must go ig you subtract 1 from the to wound roll and it would therefore not be possible to roll a 6+ to wound.

Following your post, if the sniper has something to add +1 to the wound role (and thus do mortal wounds on 6+), then the shield from harm would only bring you back to doing mortal wounds on a 6+, and therefore it is still possible.

Without the +1 to wound however, it would make it impossible to do the mortal wound.

Ops the +1 should just have been there as an example. Sorry

I'm a similar topic, would a poison weapon wound him on a 5+? Played against one the other day and that is how we played it.