I find the metallic sprays from GW tend to be a little on the transparent side, so an initial undercoat helps.

1. Prime with Mechanicus Standard Grey
2. Prime over that with Retributor Armour

Gold (Armour Trim)

1. Base with Retributor Armour
2. Shade the recesses with Agrax Earthshade
3. Highlight fine edges and sharp points with Stormhost Silver

An extra layer of Reikland Fleshshade was added to the inner flat portions of the icon.

Red-brown (Armour Panels)

1. Base with Doombull Brown
2. Shade the recesses with Agrax Earthshade
3. Highlight the edges with Tuskgor Fur
4. Highlight fine points with Cadian Fleshtone

Dark Brown (Leather pouches and Gauntlets)

1. Base with Rhinox Hide
2. Shade the recesses with Agrax Earthshade
3. Highlight the edges with Skrag Brown
4. Finer highlight with Ushabti Bone

When working on the pouches, use a rougher lined application to imitate wear on the leather.

Silver (Details and Backpack)

1. Base with Leadbelcher
2. Shade the recesses with Nuln Oil
3. Highlight fine points and sharp edges with Stormhost Silver

For grenades, replace Nuln Oil with Athonian Camoshade

Use thinned Skrag Brown to add a rust effect.

Green (Cloth Straps and Lenses)

1. Base with Incubi Darkness
2. Shade the recesses with Nuln Oil
3. Highlight the edges with Kabalite Green
4. Highlight fine points and sharp edges with Sybarite Green

Black (Armour Ribbing)

1. Base with Abaddon Black
2. Highlight the edges with Eshin Grey
3. Finer highlight with Dawnstone on the highest edges

Red (Khorne Symbols and Gun Casing)

1. Base with Mephiston Red
2. Shade the recesses with Agrax Earthshade
3. Highlight the edges with Evil Sunz Scarlet
4. Finer highlight with Wild Rider Red
5. Highlight fine points with Fire Dragon Bright

Skulls

1. Base with Zandri Dust
2. Shade the recesses with Agrax Earthshade
3. Layer the upper surfaces with Ushabti Bone
4. Highlight fine points with Screaming Skull

Horns

1. Base with Rakarth Flesh
2. Layer Skrag Brown around the base extending half way up the surface
3. Shade over with Agrax Earthshade
4. Apply thinned Rhinox Hide just at the base
5. Highlight fine points with Pallid Wych Flesh