A Stonehorn may be included in an army as a ridden monster for a Hunter, in which case the Hunter replaces the normal rider, and any shooting attacks against the model will hit the Stonehorn on a D6 roll of 1–4, and the Hunter on a roll of 5+.
Source: Warhammer Fantasy: 8th Edition
A Stonehorn may be included in an army as a ridden monster for a Hunter, in which case the Hunter replaces the normal rider, and any shooting attacks against the model will hit the Stonehorn on a D6 roll of 1–4, and the Hunter on a roll of 5+.