Which is more VERSATILE: An AR-15 in 6.5 Grendel, or an AR-10 in .308?

[mshootnit]

6.5 Grendel is not versatile at all so the default winner is 308. At least that is a capable cartridge, that can take anything in North America.

 

[luv2safari]

I'm thinking about building or buying one of these. Some factors to consider here:

- I can reload .308, and COULD reload 6.5G if I wanted (just need the dies). I already have all the stuff for .308 reloading though, and have another gun in that caliber already.
- No AR-10 will be as modular as any AR-15. I doubt I could just slap a new barrel and mag into an AR-10 and have a new caliber.
- Given the way runs on ammo happen these days, I'd like to avoid 5.56/.223 altogether, along with any components that caliber uses (.224 bullets, small rifle primers, which I suppose 6.5G also uses).
- Is anyone going to care about 6.5 Grendel in 10 years?
- I hear 6.5G has "half the recoil" of .308 in a lot of places. True?

IMO the Grendel is a neither fish-nor fowl round, not versatile.

The felt recoil of a 308 in an AR platform isn't so much. The 308 is a far more capable round. Some recoil/trigger discipline work with the 308 will have you liking that choice.

 

[bearcreek]

That word switch changes quite a lot. Versatility and practicality are two very (often vastly) different things. An AR-10 in .308 is far more versatile than any cartridge that fits in an AR-15.

 

[WVGunman]

That word switch changes quite a lot. Versatility and practicality are two very (often vastly) different things.

True, that.

 

[someguy2800]

If I were picking for what I use rifles for I would pick 308, but it would not be in an AR10, it would be a ruger SFAR or POF Rogue.

 

[LocoGringo]

16" barreled SFAR because I run suppressors.

 

[Buzznrose]

I am another SFAR owner. I also have several AR-15 in 5.56 and an AR hybrid in 7.62*39 that shoots 1.5 MOA with steel ammo (PSA KS-47).

I wish Ruger would come out with an upper in something like 6.5CM (the easy button) but I’d really like to see one in .243 or 6MM CM. Wont hold my breath for those.

I’ve debated the 6.5 Grendel upper for a few years but don’t want to go down another caliber rabbit trail at this time for that cartridge. I’d jump in for the others I mentioned. And .308 has me covered just fine for now.

 

[CraigC]

IMO the Grendel is a neither fish-nor fowl round, not versatile.

Not versatile??? It fits into ~2lb lighter platforms. Even in boltguns it comes in lighter guns, for example the Ruger Ranch compared to the Predator. It also works very well on the TC Contender pistol, as compared to the much heavier Encore. Where it basically mimics the 6.5JDJ that has been used on deer and antelope all over the world. It can cover varmints to all medium game out to 300yds using bullets up to 140gr. The .243's "versatility" is never questioned and the Grendel is much more capable than it is.

 

[luv2safari]

Not versatile??? It fits into ~2lb lighter platforms. Even in boltguns it comes in lighter guns, for example the Ruger Ranch compared to the Predator. It also works very well on the TC Contender pistol, as compared to the much heavier Encore. Where it basically mimics the 6.5JDJ that has been used on deer and antelope all over the world. It can cover varmints to all medium game out to 300yds using bullets up to 140gr. The .243's "versatility" is never questioned and the Grendel is much more capable than it is.

Excellent arguments.

I'm too old school in an era when the 30-06 ruled.

 

[anymanusa]

.

When runs on ammo occur, less predominant cartridges are the first to disappear and the last to come back..

No, they are not, this is literally the opposite of what happens. 556 is the first to go, other calibers are often not even affected as we have just seen with the Lake City happening.

 

[mavracer]

Okay, a lot of people are asking exactly what I plan to use it for. This would be my do-everything gun, the gun I just pick up if I need a centerfire rifle for almost any purpose. This would include shooting varmints from crows to groundhogs through coyote to feral pigs; camp defense against a bear, SHTF, zombie apocalypse, long(ish) range target shooting, etc.
I am not much of a rifle shooter, so even all added up I don't do most of these things combined all that often. I already own a lot of .22s, shotguns, and air rifles, so I just need one versatile rifle for all the above. I don't care if either the cartridge or the gun is the best at anything, it just has to be good enough to get the job done passably well.

When you make it about versatility there isn't anything a 6.5G will kill that you couldn't with a 308.
But how practical they are is more of a toss up. I don't have one buy IMHO the 6.5G is a really nice deer round.

 

[Eagle103]

Okay, a lot of people are asking exactly what I plan to use it for. This would be my do-everything gun, the gun I just pick up if I need a centerfire rifle for almost any purpose. This would include shooting varmints from crows to groundhogs through coyote to feral pigs; camp defense against a bear, SHTF, zombie apocalypse, long(ish) range target shooting, etc.
I am not much of a rifle shooter, so even all added up I don't do most of these things combined all that often. I already own a lot of .22s, shotguns, and air rifles, so I just need one versatile rifle for all the above. I don't care if either the cartridge or the gun is the best at anything, it just has to be good enough to get the job done passably well.

Sounds to me like the Grendel or even 5.56/.223 is really all you need unless your bear is a charging grizzly.

 

[adcoch1]

For a one and done type rifle I'd lean towards the 308, and probably in a bolt gun, but I just finished my current 6.5 Grendel build last night, and it is SO nimble and comfortable to handle that an ar-10 is further in the future than it was yesterday. We'll see how she shoots and I'll write up a thread on it...

 

[earlthegoat2]

No, they are not, this is literally the opposite of what happens. 556 is the first to go, other calibers are often not even affected as we have just seen with the Lake City happening.

We are obviously going to agree to disagree here but I guess I just have to also point out that when ammo runs occur and 6.5 Grendel (and various other cartridges) as well as 223/5.55 gets bought up and dries up, 223/5.56 production is cranked up and so is available during the droughts and lesser selling cartridges (anything but 223/5.56 and 308) only have short runs done and are quite scarce. I specifically remember having the opportunity to buy a 6.5 Grendel upper in summer of 2021 and chose not to because I could not find any hunting ammo available locally. However 223 hunting ammo was in short supply but on the shelves. Same with online unless you wanted to pay $80/box for Grendel or $35 for 223.

Im not saying 223 is a better hunting cartridge than 6.5 Grendel. However when one cartridge has available ammo and the other doesn’t, it pretty easy to see which is the better hunting cartridge.

I haven’t seen any new shortages with the Lake City happening. Vistas ammo production sale, Lake City, and the Hornady explosion (which have all pretty well happened at the same time) have not caused near the ammo crisis as the individual instances of the Obama election or Sandy Hook or the perfect storm of the Biden election, “Covid shortages” and the George Floyd riots.

 

[P Flados]

As I was reading responses, I noted most folks really did not focus on "versatility" near as much as they could have. Then you added an updated post that may help to get back to to what you really wanted to know.

Your uses do not seem to include larger game at longer ranges. The AR-10 platform is just bigger and the platform is more "versatile" if you include a likelihood that you may eventually want to operate in the "more power" side of the AR game.

The downside of the "more power" approach is that the bigger gun becomes less optimum for the uses you actually listed. Yes you can use a 308 for crows but an AR-15 gun is just way better for this end of the spectrum. The extra weight of the AR-10 also puts it at risk of you eventually deciding that it is just to much to tote around for uses where carrying an AR-15 is not a problem.

For your uses, I am betting that the AR-15 in 6.5 Grendel would do most everything you want and do it quite well. The exception is really the least likely uses of SHTF/zombie hunting. However, for this stuff the AR-15 with a cheap second upper for 5.56 is better than the 308 and it outclasses the 6.5G only by an order of magnitude. And the AR-15 with a good 6.5G upper and a cheap second 5.56 upper should cost less than a decent AR-10.

 

[CraigC]

Excellent arguments.

I'm too old school in an era when the 30-06 ruled.

You mean old school like the 6.5x54MS? Because that's essentially what it duplicates and part of why it appeals to me.

The downside of the "more power" approach is that the bigger gun becomes less optimum for the uses you actually listed. Yes you can use a 308 for crows but an AR-15 gun is just way better for this end of the spectrum. The extra weight of the AR-10 also puts it at risk of you eventually deciding that it is just to much to tote around for uses where carrying an AR-15 is not a problem.

Agreed. The .308 is no doubt a more capable cartridge, with controlled expansion 180gr bullets, elk and moose are on the table without raising an eyebrow. But if I was going to hunt those critters with a .308, it would not be an AR10. The platform just offers no benefit to justify the weight.

 

[luv2safari]

You mean old school like the 6.5x54MS? Because that's essentially what it duplicates and part of why it appeals to me.



Agreed. The .308 is no doubt a more capable cartridge, with controlled expansion 180gr bullets, elk and moose are on the table without raising an eyebrow. But if I was going to hunt those critters with a .308, it would not be an AR10. The platform just offers no benefit to justify the weight.

I've never been a fan of the old MS round, and technology back at the beginning of the 20th century passed it by. I DO love the old DT MS rifles, especially the full stocks.

A Grendel is just not suited to our hunting where I live; the 308 is much better.

 

[WestKentucky]

10mm was dying quickly but it hit a resurgence. Same could happen to 6.5 over time. No way to know. 308 is here to stay, and is common enough to sell without taking a bath on should you need to move it. 308 may be overkill for some things but not much more than a 6.5 would be. 308 gets my vote, but on the exact same line of thinking, when 223 is scarce, 308 will be too.

 

[valnar]

6.5 if all your targets are human critters or less. .308 if you think you'll stumble upon an elk too.

 

[rb288]

I have both and to be honest, my weapons are primarily for "self defense" or SHTF scenarios.
Both have their uses, but my 308 ar-10 would be more versatile in those situations.
The 6.5 will be lighter, and have less recoil, so would be better for the women and the "smaller" family members.
Overall, 308 would be a better option, ammo availability, being a primary concern.

 

[silicosys4]

Another SFAR owner here.

Agreed. The .308 is no doubt a more capable cartridge, with controlled expansion 180gr bullets, elk and moose are on the table without raising an eyebrow. But if I was going to hunt those critters with a .308, it would not be an AR10. The platform just offers no benefit to justify the weight.

Absolutely true. The standard frame AR10 is far too heavy compared to an AR15 in 6.5G for the benefits it offers, if you even needed the capacity of a magazine fed semi auto over a bolt gun.
If I were hunting elk and moose with a .308 I would be doing it with a bolt gun. You only get one tag here, and I favor using one big well placed round over multiple rounds in quick succession.
If I were hunting game that might present the opportunity for multiple shots on multiple animals in quick succession, like coyote or hog hunting, an AR15 6.5G is a great option.

I have a PA10, and an SFAR. The PA10 weighs about 14lbs with just a scope and bipod and is just ridiculous as a "hunting" rifle. Its a range toy.
The SFAR is a 16" rifle that weighs and handles the same as the average AR15. It destroys the weight arguments around a .308AR.

But again. What are you going to be hunting that requires multiple (5+) shots of .308 power in quick semi auto succession that can't easily be handled by a 6.5G?

 

[Gordon]

Besides the uncommon to obtain cartridge case this is the reason I'd never own a 6.5 Grendel. I have been shooting a 6.5 cartridge 50 years and love my 6.5 Creedmore in AR10 and other . I shot 6.5 Ugalde in IMSA in a T/C Contender. The bolt head in the AR 15 is a crucial part and actually a wearing and possible first to go part. Look whats left in a 6.5 Grendel and tell me you want to get performance loads out of it ! Also Remington did a lot of work for the Govt. with how big a reliable case could be in the AR15 format and came up with the 6.8 as the max for normal reliability. Of course there are now other weird formats for bigger cartridges in AR 15 size guns but for military , common interchange ability check out the comparsion. In a AR .450 B for instance pressures are held down for such reduction in bolt face and yes locking lugs.

 

[CraigC]

Another SFAR owner here.


Absolutely true. The standard frame AR10 is far too heavy compared to an AR15 in 6.5G for the benefits it offers, if you even needed the capacity of a magazine fed semi auto over a bolt gun.
If I were hunting elk and moose with a .308 I would be doing it with a bolt gun. You only get one tag here, and I favor using one big well placed round over multiple rounds in quick succession.
If I were hunting game that might present the opportunity for multiple shots on multiple animals in quick succession, like coyote or hog hunting, an AR15 6.5G is a great option.

I have a PA10, and an SFAR. The PA10 weighs about 14lbs with just a scope and bipod and is just ridiculous as a "hunting" rifle. Its a range toy.
The SFAR is a 16" rifle that weighs and handles the same as the average AR15. It destroys the weight arguments around a .308AR.

But again. What are you going to be hunting that requires multiple (5+) shots of .308 power in quick semi auto succession that can't easily be handled by a 6.5G?

I handled an SFAR when they first came out. If they offer a 6.5CM version, I may just have to bite.

Besides the uncommon to obtain cartridge case this is the reason I'd never own a 6.5 Grendel. I have been shooting a 6.5 cartridge 50 years and love my 6.5 Creedmore in AR10 and other . I shot 6.5 Ugalde in IMSA in a T/C Contender. The bolt head in the AR 15 is a crucial part and actually a wearing and possible first to go part. Look whats left in a 6.5 Grendel and tell me you want to get performance loads out of it ! Also Remington did a lot of work for the Govt. with how big a reliable case could be in the AR15 format and came up with the 6.8 as the max for normal reliability. Of course there are now other weird formats for bigger cartridges in AR 15 size guns but for military , common interchange ability check out the comparsion. In a AR .450 B for instance pressures are held down for such reduction in bolt face and yes locking lugs.
View attachment 1179377

Yeah but the Grendel is not going to be shot in the quantity that 5.56 is. Even with four guns, at the rate I'm going, I'll never need more than the 500rds of Starline brass I have now. If I thought it might be an issue, I'd buy an extra BCG and another 500rds of brass and never think about it again.

 

[silicosys4]

Besides the uncommon to obtain cartridge case this is the reason I'd never own a 6.5 Grendel. I have been shooting a 6.5 cartridge 50 years and love my 6.5 Creedmore in AR10 and other . I shot 6.5 Ugalde in IMSA in a T/C Contender. The bolt head in the AR 15 is a crucial part and actually a wearing and possible first to go part. Look whats left in a 6.5 Grendel and tell me you want to get performance loads out of it ! Also Remington did a lot of work for the Govt. with how big a reliable case could be in the AR15 format and came up with the 6.8 as the max for normal reliability. Of course there are now other weird formats for bigger cartridges in AR 15 size guns but for military , common interchange ability check out the comparsion. In a AR .450 B for instance pressures are held down for such reduction in bolt face and yes locking lugs.
View attachment 1179377

Engineering conquers all.
The SFAR is a .308 stuffed into an AR sized bolt face and runs at 10k more psi than the 6.5G. Here's the SFAR bolt face in the middle, flanked by an AR15 .223 bolt and an AR10 .308 bolt.

The AR15 was designed with 1950's metallurgy and slide rulers.
Times, materials, and engineering capabilities have changed.

 

[Gordon]

From what Ive seen in guns made in last 10 years or so all the engineers and materials are not impressive with ugly cheap looking designs and what every material doesn't matter much with terrible Quality control. If the CNC machines are set up by unskilled and uncaring workers where is all the advantages. On AR bolts the Grendel ones I've seen seem rather crude looking.