GURPS 4 House Rules
Section 5 - Perks

HR5.1 Shield-Wall Lockstep

You are drilled at moving and wheeling a shield wall with other, similarly trained bearers, even at a full run (but not a sprint). When running with large or oversized rectangular shields, the gaps are only 1 inch (SM -11). When stopping, you form up and leave virtually no gaps for bullets, area effect or splash weapons, though it takes a Step to hide behind large shields.