The 6.5 Grendel Option
Students of English literature know the character, but when Alexander Arms introduced the 6.5 Grendel in 2003 the name was an unfamiliar one to many firearm enthusiasts. It comes from the classic poem “Beowulf,” penned more than 1,000 years ago by a long-forgotten author.
The Grendel of lore was a fearsome beast, the first slayed by Beowulf in the epic tale. It was an otherworldly foe so indescribable that the author made no attempt to do so in the prose, although most scholars insist it was gigantic.
6.5 Grendel Stature
The modern version’s stature is well known, even standardized by the Sporting Arms and Ammunition and Manufacturers’ Institute in 2011. Its bullet diameter is a sleek 6.5 mm, and maximum cartridge length is 2.260 inches.
That’s hardly goliath when compared to today’s hard-hitting, long-distance options, although it offers unusual power for owners of modern sporting rifles—some might claim bordering on mythical in the right hands. It’s no coincidence the cartridge’s length is identical to that of a .223 Rem. Designed from the ground up to run in AR-15s and launch bullets that more often than not refuse to sacrifice energy in flight, it’s quickly become a precision favorite.
Competition shooters understand the aerodynamic advantages of a 6.5 mm-diameter bullet, but when soft-shooting and fast modern sporting rifles were just starting to go mainstream in matches, no AR-15s chambered it in any form. In 1998, North American Sportsman—headed by Arne Brennan—solved the riddle with the 6.5 PPC. It was a resounding success on the circuits, but not exactly mainstream. Janne Pohjoispää and Bill Alexander—of Alexander Arms—refined the cartridge into today’s 6.5 Grendel and unveiled it to enthusiasts in 2003.
It feeds flawlessly in AR-15 uppers chambered for the cartridge, employs the same .223 Rem./5.56 NATO magazines, enhances downrange performance when stretching the distance and perceived recoil is minimal. The 6.5 Grendel has caught on, although it has never gained the traction enjoyed by its more fashionable contemporaries.
It’s a shame, because in a gas-operated semi-auto rifle it’s positively tame to shoot, yet still manages to deliver the knockdown power needed for ethical, one-shot stops during hunting season. Ammunition manufacturers now offer a variety of different loads, including match versions, those for plinking and even opening-day options. You don’t need to look hard to find bolt-action guns for it anymore, either.
Ballistics: 6.5 Grendel vs. .308 vs. .223
Deep dives in ballistics are often a perilous, naptime journey, so let’s begin with an eye opener. Delivered from the same barrel and gun, a 6.5 Grendel can deliver more energy on a target 500 yards away than a .308 Win.
Here are the numbers, all from Federal Premium’s American Eagle line for consistency in testing protocol and results comparison. Bullet weights were selected to match as closely as possible.
At 500 yards the company’s 6.5 Grendel 120-grain Open Tip Match load hits with 747 ft./lbs. of authority. The .308 Win. Varmint & Predator 130-grain pulls in with 664. Eighty-foot pounds is a big difference when you want one-shot stops. If you’re wondering, the company’s 75-grain total metal jacket load in .223 Rem. crosses the line a distant third in the race at 514 ft./lbs.
Yes, you can go up a lot in bullet weight in .308 Win. The American Eagle 150-grain full-metal-jacket bottail load for the chambering, for example, comes in at 500 yards with1,089 ft./lbs. Recoil is increased, however, there’s a corresponding addition to the time required to deliver an accurate follow-up shot and if you want it in a modern sporting rifle, you’ll be carrying a heftier AR-10.
The .223 Rem. cartridge, despite delivering its bullets at faster velocities, is never equal or better in energy than that from the 6.5 Grendel. According to Federal Premium’s ballistics charts, the .308 Win. is the heaviest hitter inside 400 yards, where 6.5 Grendel makes the pass to permanently take the lead.
Doping the Wind
Doping those annoying breezes downrange and reading mirage are acquired skills that take practice, patience and observation. Faster bullet velocities minimize the concern by reducing the time Mother Nature has to change its course in an often-unpredictable manner.
Wind deflection data provided by Federal indicates subjecting the speedster of the trio—.223 Rem., which leaves the barrel at 2,775 fps—to a 10-mph breeze during flight drifts it only 24.6 inches off point of aim at 500 yards. At the same distance and conditions, the 6.5 Grendel load comes in at 25.4 inches, less than an inch. The slower .308 Win. adds around a foot (36.8 inches) to the adjustment equation.
Accomplished precision shooters can accurately compensate for that drift and make it look easy. Their success, however, is the product of knowledge gained by years of practice and study.
The average enthusiast, however, doesn’t spend huge amounts of time at the firing line or invest in multiple long-range courses. Even if they can, the situations they face include shifting winds in a distant valley or areas where a 10-mph breeze is considered dead calm by locals. Add autumn, when most big-game seasons begin and wind-reading foliage has dropped, and it’s obvious speed can be a decided advantage.
A variety of areas across the nation do not allow the pursuit of big game with .223 Rem. or 5.56 NATO. Energy delivered downrange and modest size of the entrance wound are among the reasons cited for the regulation.
If you are among the millions who prefer the fit, function and performance an AR-15, 6.5 Grendel provides the answer—and it’s a good one. Fire controls and manual of arms don’t change, maximizing ease of use and safety.
With the right load, the cartridge delivers more than adequate power out to distances the .223 Rem./5.56 NATO become largely ineffective. Add flatter trajectory at distance when compared to the .308 Win. with decreased wind deflection and it’s hard to find a reason not to bring an AR-15 in the chambering out opening day.
The 6.5 Grendel cartridge may not grab headlines like other cartridges, but ammunition manufacturers recognize the performance and now offer a variety of loads tailored for practice, plinking, varmint hunting, competition and big game. Although the ammo shortage of 2020 and 2021 has put a strain on supply, most of the time you can find a selection at any major big box store or online supplier.
Keep in mind the cartridge’s versatility, however. Bullet weights typically range from 90 to 123 grains, usually varied by their application. You’ll find loads with full-metal-jacketed bullets that are great budget options for plinking and practice. Ammo with soft points are available for big-game hunting, as well many with polymer-tipped bullets. Add jacketed hollow points and others, and there’s no lack of selection.
6.5 Grendel Vs. Heavier .308?
Heavier bullets have a history of performing admirably and with precision from .308 Win. chambered rifles. It can come with significant amount of additional recoil, however.
As for wind, at 500 yards the 6.5 Grendel load listed in the chart drifts 25.4 inches in a 10-mph breeze. The 150-grain .308 Win. load from American Eagle shifts off target only 23.3 (beating its lighter 130-grain sibling, listed in this chart, and besting the 6.5).
Bear in mind, 1.1 inches is significant in terms of precision, but there aren’t too many shooters who can hold what amounts to .2 MOA at 500 yards. Add moving targets, which can include stationary ones subject to the Coriolis effect, and that slight advantage vanishes quickly.
The tradeoff is the fact that the heavier .308 bullet generates 2,648 ft./lbs. of energy at the muzzle. Not all of it translates to recoil, even less is perceived recoil. It is, however, significantly more than that of the 6.5 Grendel load, at 1,815 ft./lbs. The difference, regardless of muzzle devices, recoil pads or added bulk, is noticeable.
There’s no denying the performance of .308 Win. or 7.62 NATO. But if your shots scarcely stretch beyond 600 yards, and you’re looking for a soft-shooting cartridge that runs in an AR-15 and performs downrange, odds are good you’ll enjoy a 6.5 Grendel experience.
[We'd like to extend a huge thank you to Guy Sagi for his hard work on this article. Check out our other helpful content like infographics and firearm guides. Leave a comment about what this guide helped you with most and share with your friends on social media!]