Oh... well, let me clear my reasoning then D:
- Distributing hits/wounds "as shooting" is just a way to determine who's been hit, thus Rank & File models are targeted first, then any remaining hits carry on to Characters, etc. In a full-ranked Unit above 5 models for infantry, excess hits will always kill Rank & File dudes (a unit of 10 guys is scored 20 hits, you roll against the R&F Toughness and wounds caused to that Unit will only obliterate the R&F dudes,
leaving characters untouched). (kinda need confirmation on this, can't find out where it says so)
More specifically, "distributing as shooting" implies to follow steps 4 (Roll to Wound), 5 (Saving Throws) and 6 (Remove Casualties) on the page that explains how Shooting attacks work, however since you do not follow step 1, 2 and 3, those are not necessarily Shooting Attacks (no proyectiles fired) nor Ranged Attacks (no Shrieks have been made).
Simply put, the term "distributing as shooting" implies how to remove casualties and who gets hit by _______ effect.
Now, onto the real deal:
- Hits caused by ranged weapons are Shooting attacks. They are also Ranged Attacks, and hits are distributed "as shooting" (duh!)
- Hits caused by cannonballs are also Shooting attacks that do not distribute wounds "as shooting". Why? because templates only hurt what they touch. Of course, once you've set that 4 R&F minis got killed by a catapult, you remove models from behind, but if a Champion/Character got hit (with no LOS) they get to be wounded, contrary to what "distributed as shooting" rule says.
- Hits caused by magic are not Shooting attacks, but they are Ranged attacks. Wounds are distributed "as shooting".
- Wounds caused by Death Shrieks are Ranged attacks, but not Shooting attacks. They are distributed "as shooting" though.
- Hits caused by Impact Hits and Breath Weapons while in close combat are NOT Close Combat attacks, they are Unusual attacks that generate Combat Resolution, although they are distributed "as shooting". EDIT: This... this causes me nightmares. Nowe we have 3 types of attacks, but read the Second Edit, it'll make more sense.
- Hits caused by Hexwraiths are Unusual attacks, made in the Movement Phase, that are not Close Combat nor Ranged attacks, but are distributed "as shooting".
Warmachines only use their T value when Shot at (as it explains in page 109), yet we've all seen that not every Ranged attack or hit distributed "as shooting" counts as a (normal) shooting attack. that would mean (as per RAW may I say): Spells targeting a Warmachine would use the crew's T vaule. Arrows fired against the Warmachine would use the Machine's T value.
And that's my main issue here

! Is there any FAQ that would clear out this even partially? D:
EDIT: Doing some more reading, Magic Missiles reads "as if the wizard was firing a missile weapon" at some point. So those whould use the Machine's T value. But Direct Damage spells say no such thing. Same for Vortexes.
SECOND EDIT: Upon looking at the FAQs, I found something rather interesting:
"When hits other than from shooting and close combat attacks are inflicted upon a Unit, how are these resolved? - As per the Resolving Unusual Attack's box. Note that all hits resolved in this way will count as shooting attacks for working out who is hit"
So... Flag of Blood Keep gets to save all drive-through attacks, such as Fanatics and Hexwraiths...!?
Bleh.