barrage weapons.

so a friend of mine kicked off the dust on his tyranids... so he was using the old codex.
no big deal... till the biovores hit. they got this nifty weapon with vague wording.
is whats the deal with barrage weapons? they are a Los weapon that does not require LoS, but is not ordinance ( Guess weaponry in the older rules) guess im just confused.

Moving to Rules queries section. Gob.