I don't have the tools & BALLS to build an upper by myself,
so went with Noveske's 14.5" complete carbine upper receiver.

Noveske 14.5" double chrome barrel & Voltor VIS System
Troy iron front & rear flipp sights
Vortex Flash Eliminator (Permanently Pinned)
Full auto Bolt carrier group & charging handle
Magpul angled foregrip
M9 bayonet (need extra parts to install)

Noveske 14.5" double chrome barrel & Voltor VIS Rail System
Troy iron rear flipp sight
Full auto Bolt carrier group
Magpul angled foregrip
M9 bayonet (need extra part to install)

Noveske 14.5" double chrome barrel & Voltor VIS System
Troy iron front & rear flipp sights
Full auto Bolt carrier group & charging handle
Magpul angled foregrip
M9 bayonet (need extra parts to install)

Noveske 14.5" double chrome barrel & Voltor VIS System
Troy iron front flipp sights
Vortex Flash Eliminator (Permanently Pinned)
M9 bayonet (need extra parts to install)

This is a 100% legal configuration in the People's Republic of Kalifornia