i believe steve is right the statement about ordnance using large blast is only for keyword: ordinance blast weapons.
the only part i was sold on was that the space marine codex line reads: ordnance 1 for the entry then in the back: ordnance 1, barrage. now, what exactly did gw do to errata that? because it seems like both entries would lean towards the original vindicator not getting the large blast either, because it would have to read something like "ordinance blast 1" to make it accurate. so did gw make literally 3 different stats for the same weapon?
im over the fact that blood angels gets a fast one shot anti tank cannon and not the big template-O-death but id just be interested in what gw's errata looks like for the space marine version. i mean they argue terminator armor means 40mm base, then they issue tons of models in terminator armor with 25mm bases, just to make tons of sense