Sig Sauer Sierra 3 BDX Rifle Scope 2.5-8x32 30mm SFP Reticle SOSBDX32111. The Sierra3BDX 2. 5-8x32mm is a compact and lightweight riflescope designed for ultra-lightweight rifle, shotgun muzzleloader, and crossbow configurations. With the power of the included BDX technology, it provides your exact holdover dot location on targets when coupled with a BDX capable Kilo rangefinder. Featuring exceptional SpectraCoat lenses, LevelPlex digital anti-cant, and KinEthic kinetic energy transfer indicator, the Sierra3BDX 2. 5-8x32mm is incredibly simple to use. Range a target, put the holdover dot on target, pull the trigger, impact.