6.5 Grendel Complete Guide: The Ultimate AR-15 Caliber?

6.5 Grendel
November 23, 2021 Edited March 23, 2023 12347 view(s)
6.5 Grendel Complete Guide: The Ultimate AR-15 Caliber?

While we all know and love 5.56 NATO in our AR-15s, sometimes it can feel a little behind the curve when you look at big boy rounds like 6.5 Creedmoor, .308 Winchester, or .458 SOCOM.

Thankfully, you’re never more than an upper away from a whole new rifle!

If you’ve ever wanted to reach out further and with more energy than 5.56 NATO will let you -- 6.5 Grendel might be exactly what you’ve been looking for. Further range, more power, and still in an AR-15 footprint. We got all of the details and more for you so you can see if Grendel is right for you!


History!(Because It’s Fun!)

Bill Alexander of Alexander Arms is the inventor behind 6.5 Grendel. You may also know him as the big brain behind other fun things like 50 Beowulf!

While we can all respect him as an inventor and firearms designer, I think we should give him props for his naming conventions -- Beowulf is a great poem and many of Bill’s designs are named because of it.

Grendel is the monster that attacks Beowulf’s mead hall who Beowulf slays at the start of the poem.

The impromptu English lit aspect aside, 6.5 Grendel is Alexander’s attempt to build a better mousetrap.

While 5.56 NATO can do many things, there is often been the need or at least the desire to give it a little more power. Grendel does this without sacrificing too much in terms of recoil and capacity.

However… after Alexander invented the 6.5 Grendel… things got a little strange. Alexander Arms wanted to keep the rights to 6.5 Grendel name and required payment for other brands’ use of it, much like they still do with 50 Beowulf.

To get around this, Les Baer came out with a very slightly modified barrel and bolt and started calling it a 6.5 Grendel type 1.

Alexander Arms started to be known as the type 2 and this lead to great confusion since normally 1 comes before 2.

Ol’ Bill eventually got with the program though and submitted 6.5 Grendel to SAAMI for approval as an official cartridge. As a part of that process, he had to give up any trademark claims on the name.

Since SAAMI approval, the type 1 version of the cartridge has gone the way of the dinosaurs and is basically unused these days. However, bolts and barrels made to type 1 specs can still be found if you look hard enough -- but there is no reason to use them.

Bear Creek Arsenal uses 6.5 Grendel type 2 bolts and barrels.

6.5 Grendel Rifle Shooting


Practical Applications


Likely the most fitting application for Grendel is for hunting mid-sized game. Anything along the lines of whitetail or mule deer and smaller are perfect for Grendel if you stick within about 350 yards.

For most people, 350 yards is way more than enough.

In closer range the Grendel has a lot of energy behind it and makes for a great predator or boar rifle due to the extra punch it carries.

If you want your AR-15 to have more authority, dropping on a 6.5 Grendel upper is a great option.

6.5 Grendel Benchrest shooting


Long Range Precision

Out to 400 yards, 6.5 Grendel has about the same trajectory as 6.5 Creedmoor -- granted it has a lot less energy, but it has the same drop at least.

If you’re interested in giving PRS/NRL a try with a gas rifle, Grendel is a decent option. It might not be the top of the pile, but it won’t let you down either.

Grendel has legs though and can stay supersonic out to 1,000 yards even from an AR-15, though you may want to get a 20+” barrel if that’s your goal.


Ranch Rifle

A ranch rifle is a little different and is a bit of a niche application. To me, a “ranch rifle” is a firearm that you need… on the ranch. 

If you work a piece of land, be it a ranch or some forest or anything really, you might keep a firearm with you for loads of reasons.

Maybe you work in bear country, maybe you need to stop cougars, maybe you need to protect animals, maybe you need something to humanely put down injured animals. 

Whatever your reason, you need a firearm with you. Grendel is an often overlooked but outstanding option for the role.

If you need to reach out to some range, you can. If you need to defend yourself from something with sharp teeth and claws, you can. Grendel covers a larger envelope than many other more “standard” AR-15 cartridges.



Zombies, sun flares, nuclear attack, EMPs, $GME going to 25 cents, the Moon falling out of orbit, whatever your end of the world scenario is -- Grendel will be there for you.

The downside is that 6.5 Grendel ammo might not be as easy to get as something like 5.56 NATO will be.

But the upside is that you have an AR-15 package that can pack more punch than 5.56 and can reach a long further than 300 Blackout

Both of those together make for a very attractive option if you need it.

Shop 6.5 Grendel Rifles button



Grendel falls into a nice middle ground between 5.56 NATO and larger platform calibers like .308 Winchester and 6.5 Creedmoor.

If you want to push ballistics in your AR-15, Grendel is a great round to do it with.

While it can’t replicate large-frame rounds, it can get you a lot closer than 5.56 NATO can.

6.5 Grendel Ballistics Chart

Out to 300 yards, the drop difference isn’t much to make a difference.

Past 500 yards is when things get interesting. At 500 yards, Grendel has 10” less drop than 5.56 NATO but still carries ~900 ft.lbf of energy. 5.56 NATO at 500 only has about 450 ft.lbf.

If you go by the old adage of needing 1,000 ft.lbf for hunting deer, then Grendel has you covered out to about 400 yards -- far outpacing just about any other AR-15 cartridge.

Even at the muzzle, Grendel is a major contender with about 600 more ft.lbf than 5.56 NATO and 400 ft.lbf more than 300 BLK.

There aren’t many cartridges that can over such an advantage at both CQB ranges and long distances.


Small Frame, Big Caliber

More power is more better, right? Well, not always.

If you think you need an AR-10 in your life, well you’re not wrong because AR-10s are awesome. But practically speaking, you might be better off with a new AR15 upper for your AR-15 instead.

While .308 Win and 6.5 Creedmoor have much more energy at long range than 6.5 Grendel does, 6.5 Grendel still lets you reach out on game to about 400 yards with the right ammo. That is much further than most people will ever hunt.

6.5 Grendel vs.AR-10 ballistics

And 6.5 Grendel does it with less weight and less recoil.

For paper and steel punching, Grendel is supersonic past 1,000 yards with ease. And again, less recoil.

It comes down to this:

Grendel, Winchester, and Creedmoor have about the same drop to ~400 yards. 

Grendel and Winchester have about the same wind drift to 1,000 yards. 

Grendel drops below 1,000 ft.lbf at about 400 yards, Winchester at 600 yards, and Creedmoor at 700 yards.

If you’re hunting at 400 yards or less or feel good about your wind calls for steel and paper out to 1,000, Grendel makes a lot of sense.

6.5 Grendel Barrel


Compatibility and Special Parts

One of the nice things about Grendel is that there really isn’t much you need to change to make it work in an AR-15. 

If you just want to get a complete upper, then all you need is some 6.5 Grendel magazines. Although, in a pinch -- 5.56 NATO mags work alright too, but you’ll have to down load them by a few rounds. More than once I’ve forgotten my 10-round Grendel mags at home and instead used a 10-round 5.56 NATO mag but only loaded 6 or 7 Grendels in it.

Maybe you have a spare ar upper laying around and want to build yourself a Grendel, it’s still easy!

A 6.5 Grendel barrel and 6.5 grendel bolt are all that is needed outside of the standard AR-15 upper parts. Make sure to get a type 2 bolt and a type 2 barrel (it’s really rare to see type 1 these days, but double-check to be sure).

Outside of the barrel, bolt, and magazine -- everything is the same for a Grendel AR and a 5.56 NATO AR.


Shop 6.5 Grendel Uppers button

6.5 Grendel Ammo on table


How To Choose Ammo

Something a little odd about Grendel is that it can be a little bit… haunted.

I’ve spoken with a lot of Grendel shooters and I’ve had this issue myself with two different barrels. While most barrels will like most ammo, they also almost always hate at least some ammo.

My best barrel is sub MOA with Hornady 123gr Black. That same barrel is 5 MOA with Hornady 123gr SST. I have no idea why, but my barrel just hates that SST round.

I strongly recommend that you get a wide range of ammo, just one box each, and test it through your barrel. A simple 5 round group should be enough.

Based on that 5 round group you can quickly find what your barrel will like and what it won’t like.

Once you know your barrel likes it, then stock up!


Parting Thoughts

6.5 Grendel is a great cartridge and really expands the usefulness of the AR-15. 

Be it long range paper punching or little house on the prairie living, 6.5 Grendel gives you more punch and more power at longer ranges while staying inside a normal AR-15 platform.

Tuning in an ammo load for your AR-15 rifle can be a little annoying sometimes, but the results and well worth the effort.

If you want to give your AR-15 a bit more spice, 6.5 Grendel is one of my top recommendations.


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November 23, 2021
Thank you for the very informative and well written synopsis on the 6.5 Grendel! It really is an amazing cartridge! There aren't many that can contend with it, the ones that can step to it haven't received any sort of mainstream adoption. 30Sabercat right now looks like it would take the cake as far as performance is concerned.. I wanted a different cartridge in an AR15 platform, so I built two 16.2" 300 HAM'Rs. I have handloads that are almost neck to neck with the performance you can get with 6.5 Grendel handloads. The added benefit being way more plentiful bullets, brass, and less powder. Y'all should make some 300 HAM'R Barrels! Shoot Straight and Stay Safe. Happy Holidays!
Jason Martin, Capt J
November 24, 2021
I've been a fan of the grendel for years, ever since I borrowed a friend's about 8 years ago &shot a doe on a very windy morning-240yd shot&dropped where it was!no tracking involved! I have since acquired 2 bca Gen 2 uppers-1 for my wife & I took one &put a 10.5"barrel from faxon on it,my tree stand gun! Both shoot sub1" groups @300 yds,but the 16" heavy bca barrel is much tighter shooting, more like dime size groups- with 120gr ppu,hp's,great ammo groups as good as Hornaday 123's,but much more affordable, great shooting!!,Capt J
Dennis L. Lokken
November 28, 2021
I am a little confused on your first ballistic chart. It looks like "to me", that the 5.56 with 16 inch barrel has the better ballistics than the 6.5 Grendel. the 5.56 has the brown line, which is the top line right?
January 14, 2022
5.56 does shoot flatter than 6.5 Grendel. However, 6.5 Grendel carries a much larger projectile, allowing for more retained kinetic energy/stopping power at long distances
Jasper R. Smith
December 5, 2021
I would like to know how the grendel stacks up against the 6.8 SPC.
Jason Martin
June 29, 2022
I have both& can honestly say nothing good about hunting with a 6.8spc! Have ice picked dozens of deer&hogs before I put in the safe& haven't shot since, NEVER HAD TO TRACK ANYTHING WITH THE GRENDEL! ALWAYS DRT! MASSIVE WOUND CHANNEL USING PPU 120GR HP! CAPT J
John Stamets
January 25, 2022
Ok. Please help. Is the Grendel later mod, The same as the 6.5 PRC? Can not find answer but cartridge neck size etc seems the same
February 2, 2022
We use the Grendel Type II chamber and bolt. We have not tested for the compatibility you mentioned so we can not say for sure yet however we do not advise chambering a different round in that upper, we hope this was helpful.
September 14, 2022
No, 6.5 PRC is not anywhere close to the same as the 6.5 G. 6.5 PRC takes a magnum bolt face and won’t even fit in an AR-10. Is MUCH BIGGER
Micheal Colombo
March 13, 2022
Recently purchased a 7.62 x39 BCA AND am very pleased. Was going to purchase a spare bcg for just in case but wonder if its interchangeable with the grendel?
March 14, 2022
unfortunately they are not interchangeable. we do offer 7.62x39 BCGs (https://www.bearcreekarsenal.com/ar-15/ar-15-bolt-carrier-group/bca-7-62x39-bolt-carrier-group.html).
Dalton Leach
February 21, 2024
In general practice, no. But you are on to something. When the author mentioned a Type I and a Type II Bolt and Barrel profile, he said to get a Type II. This is recommended and certainly the better route. However, your logic is not far off here. Since the 6.5 Grendel started it's life off as a wildcat cartridge, it has two separate chamber head-spacing dimensions. In the early days of the cartridge, the 7.62x39 Bolt was used. This is what is now referred to as a Type I Bolt. So a Type I, 6.5 Grendel Bolt, is just a 7.62x39 Bolt. There are very few 6.5 Grendel barrels made with this head-spacing however, because once the cartridge was officially SAAMI approved, the Type II dimensions were used.
June 29, 2022
The 6.5 looks terrible and you even admit it. Thank you for not overselling a caliber for $$$. My 450 bushmaster BCA Upper is still the take of the Town. #byebyevarmints
Jason Martin
June 29, 2022
Love my grendels! Have 3now& can honestly say that the only negative thing is ammo! I built a 6.8 spc when the fad started- but after loosing several deer & hogs that should have dropped in their tracks- BUT HAVE NEVER HAD TO TRACK ANYTHING WITH GRENDEL- ALL DRT!MASSIVE WOUND CHANNEL WITH PPU 120GR HP! and of course the ACCURACY! EVEN MY NEW BCA 10.5 " 6.5 GRENDEL IS VERY ACCURATE, just had to add aero adj.gas block & giessiele super42 spring with h2 buffer & shooting like a dream now!! Capt J
Garret Rain
June 30, 2022
I have a Grendel and like it. Liked the article. Looking at the 5.56 and 300 Blackout chart something seems wrong. The text and the chart show opposite information. The chart show more drop with Grendel and not less.
Owen Saltsgaver
July 5, 2022
I used my new 6.5 Grendel upper last weekend. I bought both Hornady and Wolf 6.5 ammo. Once I had my scope set, I ended up shooting a few .75 MOA at 100 yards with both types of ammo. That surprised me to some degree, especially using Wolf brand ammo. I only had one failure to feed using the Hornady ammo. Great cartridge.
Jack Frost
August 10, 2022
Very good article. I have one of you 6.5 Grendels with the 20" barrel. Something you left out. You can make your oen brass using 7.62x39 brass. Just reduce your powder by 1 grain . I shoot everything from 90 gr. to 140 gr. bullets. I find it's not so much the bullet but the powder weight. After I play with multiple powder weights I find I can shoot sub-moa with just about everything I load.
Denver Dude
August 26, 2022
Nice article. However, i need a little direction. I must be misreading the first chart but I can't figure out how. The text indicates the Grendel round has less drop than the 5.56 round but in the chart, line for the 5.56 is above the line for the Grendel and the chart is increasing negative the farther down you go so it looks like the 5.56 actually has less drop than the Grendel. What amn I doing wrong?
Ken Summerford
August 26, 2022
Started with 300 blackout… now I’m sold on the grendal…. Now 17 hmr is ok but really like the 17 WSM my ruger regularly shoots turkey s at 100 yards … any plans for this, understand Franklin has made some but hard to find….Thanks!!!
Doug Murphy
September 14, 2022
Good article! If I hadn't already found the 6.5G this would have sold me. I bought mine from a competitor because they offered a 24" barrel and I couldn't find one on your site. They advertised sub-moa and they delivered. After zeroing with Hornady 123gr Black I shot a 3-hole touching .297 group. I then took it out to 500 yards and it shot a 3.28" group. My Savage 10T-SR .308 that I built to shoot at 1000 yard is now retired to the safe during deer season. Thanx for the good article but you might consider the option of longer barrels.
September 14, 2022
I love my 6.5 Grendel and so does my wife, for a first time shooter, the recoil is perfect, just make sure you have good ear protection, the round packs a pretty loud bark for its size. Both my Grendel guns are running BCA barrels, and they perform as well as more expensive barrels for a lot less money. I haven't had a chance to go hunting yet, I have great confidence it'll take down whatever I aim at, quickly and efficiently
Greg Heitland
September 17, 2022
What’s a fair comparison between 6.5 Grendel and 7.62x39?
James Helms
March 13, 2023
First awesome article. Second I have been a fan off ya’ll’s stuff for a while, albeit at a distance. Not much longer, as soon as the 24 inch Grendel upper becomes available I’ll purchase it ASAP!
Roberto Gaona
July 19, 2023
What a great article! I was looking at my next rifle choices which were 6.5 Grendel or building a AR-10 from the ground up. I went with the AR-10 because I want to teach my son how to build an AR. He goes to the range with me shooting .223 (using a BCA 16" Complete Upper mind you) - and not once has it ever failed us. After reading this article and learning more about Grendel, I think it would make a nice addition to my collection. Thanks David Lane for an informative article, looking forward to reading more..
July 20, 2023
What about buffer and or gas block adjustments while using a 556 tuned lower?
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