Speer Gold Dot Personal Protection 165-grain bullets are a premier component for handloaders seeking to replicate duty-grade performance in .40 S&W and 10mm Auto. These projectiles utilize Speer's proprietary Uni-Cor technology, which electrochemically bonds the copper jacket to the lead core. This ensures that the jacket and core remain a single unit even when impacting tough barriers, allowing for deep penetration and reliable, symmetrical expansion. The 165-grain weight is highly favored for the .40 S&W platform as it provides a flatter trajectory and higher muzzle velocity than 180-grain options, while retaining more mass and momentum than 135-grain bullets. This makes it an ideal choice for serious self-defense and home protection applications.