The BSA Sweet scopes use trajectory compensation technology that was originally designed for military sniper. They feature a quick change turret system specially calibrated for multiple grain weights for the calibers: .17HMR, .22LR, .223, .243, .270. The BSA Sweet 17 AO features a long eye relief for comfortable viewing, an adjustable objective, as well as the preferred 30/30 reticle. It comes standard with 2pc dovetail rings and fully coated anti-reflective lenses all in a one-piece aluminum housing.The BSA Sweet .17 AO Rifle Scope is specifically designed for the .17 HMR. These scopes feature fully coated lenses, an adjustable objective, 30/30 reticle, 2-piece Dovetail rings and generous eye-relief. This Sweet 17 AO series features a ballistically calibrated turret for the 17 grain cartridge. Features: Fully coated lens 7.5 yd infinity parallax setting Limited 1 year warranty