Alexander Arms Ultra-Light 6.5mm Grendel AAR-15 Semi-Auto Rifle


by Jeff Quinn

photography by Jeff Quinn & Boge Quinn

August 4th, 2008




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Almost perfect. I decided to go ahead and make that statement right off the bat. No need to keep you in suspense until the end of this review. However, most Gunblast readers already know that I am a fan of the 6.5mm Grendel cartridge, and of Alexander Arms rifles. It has been about three and one-half years since I first pulled the trigger on a Grendel rifle, and it was love at first shot. The 6.5mm Grendel cartridge is a wonderfully efficient little round, designed from the inception to work perfectly through the action of an AR-15 rifle. The AR-15, properly executed, is a superbly accurate rifle, and is very easy to shoot well. It is a comfortable rifle to fire, with the recoil coming straight back, and with a pistol grip that is angled and placed for maximum comfort and control. The Grendel cartridge is a product of the fertile mind of Bill Alexander. Bill is a perfectionist when it comes to rifle design and development, and he really knows his stuff. Bill would, if time permitted, happily talk with you all day about rifles; not just his rifles, but any rifle design ever built. Unlike some in the firearms industry that develop a product and unload it upon the shooting public with little thought or attention to detail, Bill Alexander has slowly eased the 6.5 Grendel onto the market, holding back on production and licensing of the cartridge until everything was just right. He kept me waiting in severe pain for almost two years to get my Grendel. Since that early time in the life of the Grendel cartridge, Alexander Arms has increased production of the rifles and ammunition, and now offers several variations of the 6.5mm Grendel rifle. Every Grendel that I have fired has been wonderfully accurate, and this latest variation is no exception.

The Grendel rifle shown here is the lightest weight rifle offered by Alexander Arms. Weighing in on my scale at a svelte five pounds, eleven ounces with an empty magazine in place, this little carbine is a delight to carry, and comes to the shoulder seemingly without thought or effort, like a good English bird gun. The stainless steel barrel is heavily fluted. It measures .857 inch behind the gas block, and .651 from there to the integral flash suppressor, which is stepped down to just .535 inch. The total barrel length is only sixteen inches, including the integral flash suppressor, with an effective rifled barrel of only fourteen and one-half inches. The barrel is free-floated within the very thin-walled but rigid handguard, which is ventilated using a series of thirty-seven approximately three-eighths inch diameter holes. The upper and lower receiver halves are tightly fitted, and finished in a matte black. The upper receiver is of the flattop variety with an integral Picatinny rail, and has both a shell deflector and forward assist. Controls are typical AR, and easy to use. The Vltor buttstock is adjustable for length, and is very easy to manipulate and comfortable to use.

The new rifle came with a ten-shot magazine, but twenty-six round magazines are available.

I test fired the Grendel using factory ammunition from Alexander Arms and also the new brass-cased, boxer primed Wolf Gold MRT ammo, in addition to my favorite whitetail handload. Since I will be inundated with emails asking for the load recipe, it uses the Nosler 100 grain Ballistic Tip bullet loaded atop 29.5 grains of Hodgdon H-322 powder with a Remington number 7 ½ primer. The overall length measures 2.242 inches. I chronographed the various ammo to see how much velocity loss there would be from the short barrel, compared to the velocity that I get from my own Grendel that wears a 19.2 inch tube. That is a difference of 4.7 inches of effective barrel, discounting the integral flash suppressor portion of the sixteen inch barrel of this lightweight Grendel. Velocities are listed in the chart below, and are listed in feet-per-second (fps). Velocity readings were taken at a distance of twelve feet from the muzzle. The weather was typical Tennessee August weather, eighty-nine degrees and high humidity. However, I have a covered shooting position with a ceiling fan, so shooting the Grendel was an enjoyable chore. Accuracy was very good, with group sizes listed in inches or fractions thereof, fired at a distance of one hundred yards. Three shot groups were fired, allowing the rifle to cool a bit between strings. Bullet weights are listed in grains. BT and SST are polymer-tipped bullets from Nosler and Hornady, respectively. MRT is a multi-purpose bullet loaded into the Wolf Gold ammo. I am glad to see that Wolf has brought out this line of high quality ammunition for the Grendel. It allows shooters to practice using a quality round that is priced about the same as .223 ammunition, but packing a considerably greater punch.

Ammunition Bullet Weight Velocity (14.5" barrel) Velocity (19.2" barrel) Accuracy (14.5" barrel)
Alexander Arms SST 129 2291 2389 0.750"
Wolf Gold MRT 120 2325 NA 0.937"
Handload Nosler BT 100 2540 2775 0.413"

I had none of the Wolf ammo when I was chronographing the 19.2 inch Grendel, so the velocity for it is only listed for the lightweight gun. Velocity readings were very respectable from the short barrel, due to the excellent efficiency of the cartridge. Accuracy was very good with all ammo tested, even the cheap Wolf ammo grouped with plenty of accuracy for hunting. For accuracy testing, I mounted my Leupold 8.5 to 25 power Mark 4 scope. It has excellent resolution and clarity, and allows me to shoot well. For plinking and general rock busting, I used an Aimpoint red dot sight that is a very rugged and reliable unit. The rheostat has twelve settings for the intensity of the red dot, and the unit was quick and easy to use.

Shooting the lightweight Grendel was a delight. Even with the minimal weight, recoil is not a problem with the Grendel. The Grendel was developed with long range accuracy and power in mind, and that it delivers. I have fired my nineteen inch Grendel on targets out past 1100 yards with great success, and this little lightweight Grendel could serve that role as well. However, as good as it would be for long range work, the little carbine would be perfection as a hunting arm. Handling better and faster than a lever action carbine, while carrying the power and inherent accuracy to deliver precise shots at several hundred yards, this is a very versatile little weapon. It would be a near perfect walking varminter, taking vermin and predators with ease. For a whitetail rifle, whether in the deep woods or across open fields, I can think of nothing better, especially if the hunter is afoot. Also, bearing in mind that the AR-15 was developed as a fighting rifle, the 6.5mm Grendel delivers a lot more power to the target, and does it at much greater range and with superb accuracy. This lightweight Grendel is much lighter and handier than most any 5.56mm AR-15 on the market, but possesses greater power and accuracy. It would be an outstanding choice for a close-quarters fighting rifle that could double as a long range sniper. For those wanting more power from a fighting rifle than the 5.56mm provides, the 6.5mm Grendel is an excellent choice, and in my experience, greatly outperforms the 6.8 SPC cartridge.

At the beginning of this review, I stated that this ultra light 6.5mm Grendel was “almost perfect”, and it is. Perfection can be achieved easily by ordering the rifle with the optional Tactical Trigger as offered by Alexander Arms. I have the Tactical Trigger in my personal Grendel, and it has spoiled me shamelessly. It could just as well be named the Target Trigger or Hunting Trigger, as it is superb in those roles as well. While the standard trigger in this carbine is better than most AR triggers, it measures four and three-quarters pounds, with typical AR creep. The Tactical Trigger is worth the extra price. For only about $185 extra, you can achieve perfection in an AR-15. The Tactical Trigger is money well spent, and will most likely make this lightweight Grendel shoot even more accurately. This little carbine has it all; light weight, accuracy, good looks, and power. It is easy to shoot and a delight to handle. I highly recommend it.

For a look at the entire line of Alexander Arms products, go to

For the location of an Alexander Arms dealer near you, click on the DEALER FINDER at

Jeff Quinn

NOTE: All load data posted on this web site are for educational purposes only. Neither the author nor assume any responsibility for the use or misuse of this data. The data indicated were arrived at using specialized equipment under conditions not necessarily comparable to those encountered by the potential user of this data.  Always use data from respected loading manuals and begin working up loads at least 10% below the loads indicated in the source manual.

For a list of dealers where you can buy this gun, go to:


The Laserlyte Kryptonyte Green Laser Boresighting Kit is an invaluable bench tool.



For serious accuracy testing, the Leupold Mark 4 8.5-25x scope never fails to deliver the best a rifle has to offer.



Wolf has added the 6.5 Grendel to its Gold Line ammo.



Whether using inexpensive factory ammo, premium factory ammo, or handloads, the 6.5 Grendel is a real tack-driver.



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Click pictures for a larger version.


Alexander Arms' Ultra-Light 6.5mm Grendel AAR-15.



Left to right: author's 6.5 Grendel Entry Rifle, new lightweight Grendel, 16-inch AR-15 5.56mm carbine.





Vltor adjustable buttstock.





Integral flash suppressor.



Heavily fluted barrel reduces weight and aids rapid cooling.



Further weight reduction and cooling are facilitated by use of a composite ventilated handguard.





Upper receiver features case deflector and forward assist.



Ten-shot magazine.





Aimpoint red dot scope.