There's a section for queries and questions, I think..,
Nonetheless, such weapons are found in the Wargear section, alongside Heavy Weapons.
Special weapons are a subheading of ranged weapons, and as evinced in their name, they're more exotic and expensive than regular standard issue guns
Blasters, Shredders, Haywire Blasters* & Heat Lances**
** Scourges and Reavers only
As far as your Kabalites are concerned, a typical unit might be 5 Kabalites, 4 of which have regular splinter rifles, and 1 of which can trade his splinter rifle for either a Shredder or a Blaster (always pick Blaster).
You could also opt to buy a heavy weapon in much the same manner, except it requires at least 10 Kabalites in a unit to purchase. For example, 10 Kabalites, 8 which retain their splinter rifle, one which trades his splinter rifle for a special weapon (always pick Blaster) , and another which swaps his splinter rifle for a heavy weapon (your choice of Dark Lance or Splinter Cannon).