There's a distance where the velocity of a jezzail round will overcome even Dwarven steel, and you've done your best to estimate it. Through gaps in the lines humans march at double time, pavise shields before them, freshly reinforced with the strongest steel Karak Azul can provide. Perhaps having some premonition of the future, perhaps merely preferring a larger target, the jezzail rounds concentrate on them only to ricochet off. They reach their preferred range and with a percussive chorus, the shields slam down upon stone, and then a second chorus sounds as cunning Tilean devices drive steel rods into the stone below. One of them are unfortunate enough to catch a jezzail bullet in the fraction of their head that is visible over the top of the shield, but a second shot of warp lightning grounds harmlessly against a stone wall instead of interfering with them, and a moment later Braganza's Besiegers demonstrate just how they got their name. Any unit of crossbowmen can pull their weight when defending a fortified position, but it takes something special for one to make a name assaulting them, and with utter discipline the crossbowmen begin to fire, not as a volley but as a constant rhythmic pattern to prevent any wasted shots on already-doomed targets. Jezzail snipers scream and gurgle, Fangleaders foolish enough to wear the plumes of their rank topple over, and with a shattering of glass the Underway is plunged back into darkness. The Dwarves march on.