The 6.5 Grendel is a centerfire rifle cartridge introduced in 2003, designed to give the AR-15 platform improved long-range performance over 5.56 using efficient 6.5mm bullets. It is popular for target shooting, moderate-range hunting, and recreational use.

The 6.5 Grendel was introduced in 2003 to address a specific limitation of the AR-15 platform: extending its effective range beyond what the 5.56 offers, while still fitting the standard rifle. It uses an efficient case and the aerodynamic 6.5mm (.264 caliber) bore to deliver better downrange ballistics from the same compact platform, requiring a different barrel, bolt, and magazine. Ballistically the 6.5 Grendel fires aerodynamic 6.5mm bullets — commonly around 90 to 130 grains — at moderate velocity, producing a flatter trajectory and better retained energy at distance than the 5.56, with mild recoil. That combination made it a popular choice for shooters wanting more reach and effectiveness from an AR-15 for target work and for hunting deer-class and smaller game at moderate range. It predates several of the newer AR-platform cartridges and established a durable following, with a solid base of barrels, ammunition, and components. It occupies a niche of improved-range AR-15 performance alongside more recent options like the 6mm ARC. Today the 6.5 Grendel is used for target and recreational shooting, moderate-range hunting, and varmint hunting, with steady availability in the AR-15 platform. Its pairing of efficient 6.5mm ballistics with AR-15 compatibility and low recoil is why it became a well-established improved-range option for the platform.

General information about this caliber — not a recommendation for this specific firearm.