This could be a 7 with more highlights. Even higher with weathering/rust effects. Vallejo do a pot they call 'Metallic Medium'. I found (very recently) that it works really well for edges as it seems even brighter than Mithril Silver (you can also mix it with colours to get metallic colours better than Citadel paints). I'd be happy with this dude in a gaming army.
solid enough paintjob, the photo is a bit dark but from the look of it i would suggest further highlights to the metal work. a wash of devlan mud on the skulls and a further highlight to the red would help this rank higher, hope that helps