The Hercules-Corona Borealis Great Wall (HCB Wall) is an enormous structure of galaxy superclusters spanning approximately 3 to 10 Gly, one of the largest known structures (Horvath 2014; Clowes 2013). Its existence challenges ΛCDM because structures of this scale should not have had time to form through gravitational collapse since the Big Bang under standard growth rates, and it exceeds the theoretical upper limit predicted by inflationary cosmology.
The standard model assumes hierarchical structure formation with a maximum coherent-structure size below the cosmological-principle scale of roughly 300 Mpc. The HCB Wall at multi-Gpc scale exceeds the model's largest predicted coherent structure by an order of magnitude. The model has nowhere to go except by abandoning the cosmological-principle assumption or by attributing the structure to selection effects in the gamma-ray-burst tracer.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, the HCB Wall is a first-stage cascade-collision wall signature at the parent-pocket scale. The cascade has a finite largest characteristic scale Λ_max ≈ 2 × R_pocket ≈ 5 Gpc set by the parent-pocket size (P55). First-stage near-head-on cascade collisions (P22, P33) produce wall structures up to this scale.
The HCB Wall + Big Ring + Giant Arc + Sloan Great Wall + CfA2 Great Wall + Actinoide Arc are all members of the predicted gigaparsec-population P55, with roughly 3 to 7 such structures per observable patch. Multi-stage cascade dynamics (P36, P37, P38, Section D2) sets the formation context: each wall was deposited by a specific cascade-stage collision rather than assembled gravitationally over cosmic time. Pre-existing matter from prior cycles (P25) supplies the baryon budget that gets thermalized into the wall structure.
Angular-momentum inheritance (P31, P32) propagates the cascade-axis through the wall, producing predictable spin-orientation and filament-direction signatures along the wall axis. The same M4 framework that produces the Sloan Great Wall (recid 99), the gigaparsec ring-and-arc structures (recid 85), the supervoid demographics (recid 95), and the cosmic-web morphology produces the HCB Wall as a predicted first-stage cascade product. There is no need to abandon the cosmological principle or to invoke selection effects in the GRB tracer.
If precision Euclid + DESI + CTA gamma-ray-burst-cosmology surveys find no walls at the gigaparsec scale beyond cosmic-variance expectations (no 3 to 7 per observable patch population), the M4 first-stage cascade wall explanation is refuted. The signature SCT prediction is the gigaparsec-wall population at Λ_max ≈ 5 Gpc with the predicted demographics.