TEXT: Chapter Approved – Codex: Space Wolves clarifications (v1.0)
  The Stormcaller power can cause some confusion, so the following notes should
  help.
  • Remember that plasma and frag grenades only work if the unit that has
  them charges. If a unit with Stormcaller on it charges an opponent with
  either grenade type they will strike first as these grenades are of no use
  when receiving a charge.
  • If charging a unit in cover, then all attacks are simultaneous.
  • Stormcaller can be cast on friendly vehicles, which then count as being
  hull down.
  Remember that cover only matters in the first round of a close combat and
  subsequently attacks will occur in normal order. New enemies charging the unit
  with Stormcaller will be affected though. Weapons that strike last will, of course,
  always strike last.
  The Head-strong rule states that "Blood claws must charge if one of their models
  is within 6" of the enemy, unless led by..." a character. This means that the Blood
  Claws cannot rapid fire their bolt pistols if the enemy is within 6" as this would
  prevent them assaulting.
  A Rune Staff counts as a single-handed weapon AND a psychic hood, it should
  therefore cost 25 points.
  Wolf Scouts may not choose weapons from the options included in the Space
  Marine Scout entry in Codex: Space Marines and from Codex: Space Wolves list
  as well.
  When operating behind enemy lines in a mission where the enemy is not allowed
  any reserves, Wolf scouts arrive on the table edge the enemy retreat towards. If
  they fall back then they retreat towards this edge too.
  A Wolf Guard Battle Leader may not take a Mark of Wulfen.
  A character accompanied by Fenrisian Wolves is a Mixed Armour unit as is an
  Iron Priest accompanied by a Thrall bodyguard.
  Space Wolves may not hit Dark Angels vehicles (other than Dreadnoughts) on a
  3+ in close combat. The 3+ only applies when fighting something with a WS
  attribute.
  A pack of Blood Claws or Wolf Scouts may not be led by a Wolf Guard in
  Terminator armour. Note this is an amendment more than a clarification but
  
  removes the need for more clarifications to resolve contradictions that the
  combination creates. In all other circumstances units led by Wolf Guard in
  Terminator armour cannot sweeping advance after close combat and can only
  consolidate.
  A Wolf Guard Battle Leader does not use the Wolf Guard column in the Space
  Wolf armoury when selecting weapons and wargear.
  If a model with a Wolf Tooth necklace is fighting a Dire Avenger Exarch with the
  Defend power (Necklace always lets you hit on 3+, Defend says opponents only
  hit on 6+) roll a d6 each round to determine which piece of wargear has priority.
  A Wolf Tooth Necklace has no effect on enemy vehicles without a Weapon Skill
  characteristic.
  A Wolf Guard Battle Leader does not count as one of the 20 Wolf Guard models
  you are allowed to have in a Space Wolf Army.
  Wolf Guard Terminators may have a single-handed weapon in addition to a
  heavy weapon (this supercedes the note in the Wolf Guard list entry). If they
  have a cyclone launcher they may have a storm bolter instead of a single-handed
  weapon. In addition, they may select Runic Charms, Wolf Pelts and Wolf Tooth
  Necklaces as if they had a ‘T’ next to their cost in the Space Wolf Armoury.
  Long Fangs do not have a Razorback listed as a transport option.  This is an
  oversight, Long Fangs may purchase a Razorback for the cost listed for Grey
  Hunter squads.
  The True Grit rule does apply to all combi-weapons but not to storm bolters.
  If a Runic Charm is combined with Terminator armour it does not allow a re-roll of
  the Crux Terminatus Invulnerable save that comes with the armour.
  If a Wolf Priest takes Healing Balms, and is escorted by a Wolf Guard bodyguard
  in Terminator armour, the balms do not allow the bodyguard to ignore the first
  failed save made against the Terminator’s 5+ Invulnerable save.
  Fenris Wolves can ride in a transport along with an Independent Character but
  cannot ‘run along’ outside the vehicle.
  The Land Speeder Tornado should cost 75 points before weapon upgrades are
  selected.
  Blood Claw packs equipped with jump packs instead of being mounted on bikes
  will automatically have frag grenades and krak grenades. They may additionally
  have meltabombs at +5 points per model.
  
SOURCE: textdata/thevault/Warhammer/40k/1st-8th Editions (Prior)/Errata/Warhammer 40k - Errata - Space Wolfs QA.pdf