The 6.5 Grendel is a stubby little thing that, when not properly juxtaposed, looks smaller than the 5.56, everyman’s favorite AR cartridge.
But it’s a great cartridge, and it has a lot of practical uses. So, if you’re thinking about going the route of a complete upper receiver for your next build and already have a 5.56, consider the 6.5 Grendel.
Here’s what you should know.
Why 6.5 Grendel for Your AR Build?
The 6.5 Grendel is an intermediate cartridge that was designed, curiously, from a Russian parent case, the .220 Russian (more formally, the 5.6x39mm), an early 1960’s cartridge that was developed for deer hunting.
The purpose of the creators was to come up with a cartridge that could be used with STANAG AR magazines, but which offered better performance than the 5.56x45mm NATO cartridges around which they were designed.
The new cases were shorter, but with a larger diameter, enabling them to accommodate a larger propellant charge as well as different bullets that delivered a higher ballistic coefficient.
While they can still be used with STANAG AR magazines, there is a slight reduction in capacity, and a different bolt carrier group and barrel must be used.
All the same, the designers got what they wanted. Loaded with bullets typically weighing between 90 and 130 grains, the 6.5 Grendel can deliver muzzle velocities and energy in the area of 2500-2900 FPS and 1800 ft-lbs, respectively, although these figures vary according to load data, barrel length, and other factors.
So, with that said, what are some reasons to complete an AR build with a complete upper receiver for a 6.5 Grendel? Here are some good reasons.
The Draw of 6.5 Grendel
Wondering if it makes sense for you to start a build with a complete AR upper receiver for a 6.5 Grendel AR? Start with these.
1. You get to keep your mags (and other parts, too, actually)
Remember, the 6.5 Grendel was designed in part for a cartridge compatible with standard AR magazines. That said, 5.56 mags can only hold a smaller capacity. A standard 30-round mag will only hold 26 rounds of 6.5 Grendel, for instance.
Actually, you’ll get to use a lot of parts, too. The platform for 5.56 and 6.5 Grendel uses the same parts except for the bolt, barrel, and barrel extension, so you can pretty much use the same parts as you would for a 5.56 build. It also means you can use a standard lower parts kit (and lower receiver) to build a 6.5 Grendel rifle. All you need is a complete upper receiver chambered in 6.5 Grendel.
2. Much more powerful, particularly downrange
This is probably the most important argument in favor of 6.5 Grendel as a cartridge. It far surpasses the ballistic performance and stopping power of the 5.56 NATO and .223 Remington, and handily at that.
At the muzzle, a 123 grain 6.5 Grendel bullet will produce muzzle energy of about 1800 ft-lbs, about 50% more than a comparable 5.56 load (with a 55 grain bullet) would produce. Moreover, it retains that energy better.
At 500 yards, the same 6.5 Grendel bullet will hang onto almost 900 ft-lbs of energy, whereas the same 5.56 bullet will have shed almost 80% of its muzzle energy, retaining just under 300 ft-lbs.
3. Better ballistic coefficient
Naturally, what follows, given the figures brought to light in the last section, is that 6.5 Grendel offers far superior ballistic coefficient than the 5.56 does. This is manifested both in bullet drop as well as in wind drift.
Take the same 123 grain bullet, and it will exhibit about half the propensity for wind drift of the 5.56 with a 55-grain bullet. On top of that, it hardly drops any faster. At 300 yards, and zeroed at 200, the 6.5 would drop 9.2” to the 5.56’s 7.2”, and at 500 yards, the 6.5 would drop only 52.8” compared to 47.7” for the 5.56. That’s hardly a difference, especially for a bullet that weighs nearly three times as much.
4. Better overall long-range performance
Given what has already been illustrated about the 6.5 Grendel, it makes it a high-quality long-range performer. True enough, it drops hardly any more than the 5.56, and with any sort of crosswind, it is the clear winner.
Now, if all you’re doing is making steel sing, it’s not a big deal. Maybe 5.56 is better because it won’t be as hard on the targets. But, if you’re using it for a sporting application, the Grendel takes the cake.
5. Reasonable cost
Here’s the thing. The 5.56 is a cheaper round, no matter how you slice it. It’s produced for the military so there’s always a steady supply and you can usually get really good bulk or surplus deals.
On average, 5.56 (depending on the type of bullet and load data) will cost somewhere between 45 cents and a dollar per round. That’s really cheap for a centerfire cartridge.
But, despite the fact that the 6.5 Grendel is more expensive, it still won’t break the bank. They usually cost between just under a dollar and 2 dollars for a round. That’s not so bad, considering how much more performance the round delivers.
6. For sportsmen, 6.5 Grendel is a good option for hunting
Last consideration - this cartridge delivers much better ballistic coefficient and stopping power than 5.56, especially at long distances, where it matters. This makes it a far superior cartridge for hunting small and intermediate game, where legal and relevant.
Not that it’s going to supplant .223 for ‘yotes and foxes, but for larger game, it’s probably a better bet.
Starting with a Complete Upper Receiver
Getting ready to build a complete AR-style rifle around 6.5 Grendel? Start with a complete upper receiver, and get the rest of the AR lower parts, charging handles, gas systems, and anything else you need right here at MCS Gearup. Also, feel free to reach us at Sales@MCSGearup.com if you have any questions about your builds.