My upper is Del-Ton. The lower is Cavalry Arms.
It has been nothing but 100% awesome reliable. It's a 2MOA bench gun with sloppy-constructed 55gr surplus bullet handloads. It's around 1MOA with PPU 75gr match.
From prone, I hold it to about 3MOA if I really focus.
You guys shooting steel: You ever wonder why the army doesn't use steel cased ammo in their guns?
It's because the chamber isn't tapered like an x39 chamber is. Steel in a NATO chamber (5.56x45 and 7.62x51) will grip, because those two chambers are straight along the body of the brass. x39 chambers taper with the body.
NATO chambers aren't designed to shoot steel cases. NATO specs call for brass casings.
IMO, brass/steel is a non-issue in a responsible NATO-chambered gun owner's mind. If you want to shoot cheaper steel cased ammo, get an upper in 7.62x39 or 5.45x39. Otherwise, shoot ammo that was designed for your chamber.
Wolf/Silver Bear aren't used by the Army or Marines for a reason. Regardless of the potential short term cost savings.