We build complete uppers to order.
Below is a standard configuration upper built on DPMS lowpro receiver with carbine handguard and low profile gas block.

Below is a standard configuration upper with a 16" semi-bull profiled barrel and rifle length handguard.
Options are almost endless, including muzzle threading, flash hiders & comps, A3/A4 receivers, quad railed handguards,  adjustable gas blocks, adjustable gas tubes, folding front sights, extended height receivers and side charging handle receivers. Some examples are shown below.

Shown is a 223 upper with 24" Krieger Supermatch barrel, Painted Flutes, Semi-Bull Profile & JP adjustable gas block built on a Rock River EOP receiver, Badger handguard with rail added for TDI bipod and M6 illuminator.

Shown is a 5.56 upper with M4 receiver, 14.5" Mid-Length gov't profiled barrel and Daniel Defense 9.0 handguard. The barrel has a Sabre Extended A2 comp permanent attached to reach 16" minimum length.

Shown is a 204 Ruger upper with A4 receiver, 24" stainless heavy barrel and rifle length handguard.

Here is a 223 upper with a 16" mid-length barrel, 10" Knights RAS, adjustable low profile gas block and Smith Vortex FH.

Shown is a 16" SPR mid-length barrel on an M4 receiver, LaRue 9.0 handguard, PRI flip-up front sight, ARMS #40 flip-up rear sight and a Smith Vortex flash hider. Lower has LMT SopMod and Tango Down Battlegrip.

Here is a basic M4 upper with a 14.5" gov't profile barrel using the carbine length gas system, Daniel Defense 7.0 handguard with a  permanent attached  Phantom FH to get to 16" minimum length.

Shown is a 300-221 upper with A4 receiver, 16" Medium profile barrel in a dissipater setup with a PRI folding front sight and rifle length C-More handguard.