6.5 Grendel Ammo

6.5 Grendel: In Depth

AR-pattern guns have proven to be some of the most versatile and adaptable firearms in history. While the shooting public now has access to dozens of cartridges that work in this platform, this wasn’t always the case – because they didn’t exist before about 2001. The massive market in the US for these cartridges arguably was just beginning to take its baby steps at that time, aided in part by the expiration of the Federal Assault Weapons Ban in 2004 and the ongoing GWOT (Global War on Terror). Specialized military units often expressed the need for more impact authority from a .223 Remington-length cartridge – that would function in an AR – which would lead to cartridges like .458 SOCOM and .300 AAC Blackout, among others. However, none of these were around in the late 90s when Bill Alexander began development on a 6.5mm cartridge that would soon take a fearsome and memorable name.

Named after the fictional beast of Old English literature fame, the 6.5 Grendel was unveiled in the midst of the GWOT – at a Blackwater training facility, of all places. Targeting the performance and range of 7.62x51mm in a more compact, AR-15-length package was the basis for the Grendel’s design. For a parent case, Alexander chose the 7.62x39mm; PPC cases, which are based on the .220 Russian – which itself is based on 7.62x39mm – are said to have heavily influenced the 6.5 Grendel. This was then necked down to 6.5mm and given a projectile in the same weight class as the Soviet standby – 123-gr. Impressive effective ranges and results on target were achieved with this combination, and all of this through an AR-15 platform rifle.

Although popular in its own right, 6.5 Grendel also donated more than a dash of DNA to the later 6mm ARC and .22 ARC cartridges. Both use the Grendel’s case and neck down to their smaller diameters. And, while these may be more appropriate for predator hunting and varmint hunting, respectively, 6.5 Grendel is still the best among the three for medium-sized game hunting. 

Given the pattern of development over the past decade, more Grendel-derived cartridges are likely on the way, too. There might be no limit to what a capable group of tinkerers and engineers can squeeze out the AR-15 platform in the years ahead.  

6.5 Grendel: Guns

From the outset, this was meant to be a gas-gun cartridge, and more specifically for US shooters, an AR-15 cartridge. SAAMI spec for overall length (OAL) is 2.260”, which is the same as .223 Remington. As a result, most guns chambered for 6.5 Grendel are AR-15s, at least in the US. However, since this cartridge is based on the 7.62x39mm, it’s an ideal candidate for service in an AK-platform rifle as well, though these guns are mostly overseas. Serbia’s Zastava M19 is one example. Lightweight bolt-action rifles by Ruger and Howa are ideal for predator hunts, and will get you a bit more velocity compared to an AR.

Semi-Auto Rifles

  • Alexander Arms Tactical
  • Radical Firearms RF-24
  • CMMG Dissent

Bolt-Action Rifles

  • Ruger American Predator
  • Howa M1500 Mini Hunter

Why Choose 6.5 Grendel?

Although 6mm ARC has stolen the spotlight over the past few years, 6.5 Grendel is still a relevant cartridge that has utility across the board. For starters, it helped usher in the new age of high-performance AR-15 compatible cartridges that we all enjoy today. At the time of its development, .300 AAC Blackout, .224 Valkyrie, .350 Legend, and other compatibles were not yet available. It also uses the proven capability of 6.5mm projectiles within an AR-15’s action, which is useful for a number of match, hunting, and tactical shooting applications. In addition, the Grendel’s larger projectiles are better for hunting medium-sized game or for medium-range military use vs. the newer 6mm ARC.


  • Better performance vs. .308 Win. / 7.62x51mm at long range, with less recoil.
  • Superior wind performance vs. .223 Remington / 5.56 NATO.


  • More than enough power to get the job done on hogs or predators and capable of taking medium-sized game like deer and antelope.
  • Ideal AR-15 hunting cartridge, but also a great performer in a lightweight bolt-action rifle.


  • Factory FMJ loads available for tactical / training purposes.
  • Bests 62-gr. .223 Remington in energy ft-lbs. 
  • Compatible with the AR-15 platform.

6.5 Grendel: Ammo Brands and Loadings

Typically, this round is factory loaded with bullets ranging from 90-gr. to 129-gr., with muzzle velocities between 2,300/fps to 2,700/fps. While you might think that’s low compared to something like 6.5 Creedmoor, which is typically loaded with a 140-gr. @ 2,750/fps, don’t forget that we’re talking about an AR-15 length cartridge vs. the Creedmoor’s AR-10 length. This is a capable cartridge in a small package. Big names like Hornady, Federal, and PPU all load this round, as well as lesser known manufacturers, like Alexander Arms (the company that developed 6.5 Grendel). Also, steel-cased ammo from Wolf is available when import bans on Russian ammunition are not in effect. 


Standard Loading

  • 123-gr. Polymer Tip or Hollow Point @ 2,580/fps

Bullet Types

  • Polymer Tip - Target, hunting
  • BTHP (Boat Tail Hollow Point) - Target, hunting
  • FMJ (Full Metal Jacket) - Target

Bullet Weights

  • 90-gr. to 110-gr. - Target, hunting
  • 120-gr. to 123-gr. - Target, hunting
  • 129-gr. - Target, hunting


  • 90-gr. to 110-gr. - 2,700/fps
  • 120-gr. to 123-gr. - 2,580/fps
  • 129-gr. - 2,400/fps

6.5 Grendel: Frequently Asked Questions

Yes! It was designed to be compatible, and shares the same OAL (overall length) of .223 Remington. You will need a different upper and magazines, however, as it is a different caliber.

Hunting loads are available for everything from varmints and predators up through hogs and deer. 

Not really. Although 6mm ARC has a number of impressive features, 6.5 Grendel hits harder and is better for hunting medium sized game. Also, they represent different use cases, so they don’t necessarily compete with one another.