U4GM Where Sniper Turrets Drop Sentinel Firing Cores in ARC Raiders Welcome to U4GM—if ARC Raiders' wipe reset's got you rebuilding, we've got you covered with no-ness tips and the stuff you actually need. Sentinel Firing Cores for Gunsmith Station lvl 3? Hit Dam Battlegrounds first: sweep both sides of the broken dam for Sniper Turrets, then check the Research & Admin corner, and at night watch the Blue Gate lasers for easy spots. Go quiet with Raider Tool melee or a quick Snap Blast from behind, stash the core, and extract.