Just won this one at Holt's auction last night. GES. STEYR .375 EX 'M1910' BOLT-MAGAZINE STUTZEN SPORTING RIFLE, serial no. 2860, 19 3/4in. nitro barrel, ramp-mounted bead fore-sight, leaf rear-sight with 1 x folding, manual flag safety, turn-down butterknife bolt, set triggers, detachable floorplated, 14in. well-figured full-length pistolgrip stock with cheekpiece, sling swivels. Anyone have an idea what that perforated piece of metal is about over the chamber?