Winchester USA Ready Defense 10mm Auto 170gr HVHP Centerfire Handgun Ammo - 20 Rounds - Winchester's USA Ready Defense Line is a continuation of the USA Ready sub-brand. Each lot is controlled and has ballistic information available online. USA Ready Defense targets growth with CCW enthusiasts and new home defense gun owners. The new Hex-Vent bullet prevents hollow point cavity from clogging with barrier material while directing fluid flow into the hollow point to initiate expansion. Tested for 12+in penetration and retains 95% of its weight.