How's that for a magazine article title? :-)
I came to the Grendel the long way. I wanted a round I could hunt big game with in an AR. I tried 6.8 SPC. I tried 308. I dabbled with 300blk. None would do what I wanted. A friend had told me to get a Grendel, before I ever went the 6.8 route, but I thought that was a nutty choice, so I stuck with my plan. Well, he was right all along.
What was I looking to accomplish? I have worn out a 14.5" 5.56 AR just about every year for the past 13 years or so, sometimes more than one. I get about 20,000 rounds out of an upper, and then it is too far out of spec to do what it should do. Shorter guns last less, sometimes quite a bit less. I've seen between 5,000 and 10,000 from the shorter guns. That equates to right around a quarter of a million rounds through the AR. That doesn't seem like very much to me, when you look at my pistol logs, but it is what it is.
Over the last 13 years, I have come to really appreciate the design of the AR. Considering it's uncertain beginnings, it really has proven to be the Rifleman's Rifle. I say that because not only is it the military arm against which all others are judged, but it has taken over in most forms of rifle competition as well. In some cases it is an actual semi auto AR that is used (think things like service rifle, or 3 gun), but in other cases it is simply that the AR's fantastic ergonomics have been stolen for use in bolt guns or even single shots. Look at all the chassis systems out there in use in various practical rifle competitions, like PRS. Also in across the course guns, like the Tubb's 2000, and the host of tube guns used in that arena. I could keep going but I think you get the idea. The AR ergos are here to stay, and we are well off because of them.
My main use of the AR is as a weapon, but if I can take advantage of the ergos, weight and size, while launching a big game killing round, then it seems that I can have my cake and eat it too. So, now that the gun has been chosen, what about caliber?
I, and may others out there, have happily hunted anything they could hunt in North America with a 308. If you pick an appropriate bullet, and place it where you should, the game will die very quickly. There are many fine choices in caliber today, but the effectiveness of the 308 is not really up for debate. Unfortunately, the AR has to grow a fair bit before it will accept a 308. I have some of those and have had others over the years that are gone now. They are great guns, and I have carried one or another on several continents, but for pleasurable field use, I think they are a tad to big. So, how can I get 308 ballistics in an AR-15 size package? The 6.8spc comes close, and for pure hunting out to 300 yards, it can be a good choice. In my case though, I wanted more accuracy than the 6.8 seems to want to give. My ideal AR hunting gun was conceived on the plains of Montana, and though the initial shot never need be far, a wounded animal can run far and fast, so a follow up shot might need to be taken at longer than normal ranges. In addition, coyotes are fair game at most ranges, so a gun that can reach out there is a good thing.
As a rifleman, I want a gun that can hit anything I can hit, under any circumstances. The little Grendel does that, and it does it very well. Add a good sling that allows for a solid loop up, and you have a package that is about as capable as any rifle ever fielded.
The 6.5 Grendel offers about 80% of the terminal ballistics of the 308, while offering better wind bucking and a flatter trajectory, especially at long range. The differences in external ballistics are not enough to jump up and down about, but neither are the differences in terminal ballistics. Yes, the grendel is going a bit slower than more traditional 6.5 cartridges, but the long 6.5 bullets are built well and fly well. Even at slower velocities, they pack good killing penetration.
Hornady makes inexpensive, match grade factory ammo. In my gun the 123 SST will hold .5 moa for 5 shots, and it drops deer on the spot as well. Coyotes and foxes have no chance, and the precision of the round makes the small vitals of a fox almost easy. If you need bigger game penetration, the 120 TTSX will do the job, though it does not have quite the longer range capability of the SST.
My gun is a custom one, assembled by a family friend who no longer builds Grendels for the public. It uses a Lilja barrel, and is as capable of 1000 yard shots as any 308 I have. If I needed one today, I would start and stop my search at Precision Firearms. They have all sorts of sizes, weights, accuracy levels and price.
One really important thing to keep in mind about the Grendel. I consider it to be an enthusiasts cartridge. Not suitable for mass issue. Not suitable as a general purpose weapon. I have no idea if it would pass a military trial, but I suspect it would not. The bolt face has to be opened up a fair bit to accommodate the bigger brass, and early Grendels had some durability issues becasue of that. Current ones seem to be good, but I don't really care if they are or not. It is a sporting arm for me, and in that arena, it excels.
I'm sure I forgot to address some issues, so feel free to ask or add.