rebarreling AR, 6.5 or 6.8

[greyling22]

I'm going to rebarrel my ar. I'm leaning toward either the 6.5 grendel or the 6.8 spc. It is going to mostly punch paper, and I'd like it to do MOA or better with my handloads, but also spend time hunting hogs at 50-175 yds. It would also be nice to be able to strtech out to 500 in a pinch to take a shot at an antelope. but that would be very infrequent. Basically I want something with longer legs and more punch than a 223 without buying a new AR in 308.

6.5 grendel is theoretically a better long range gun, but I would not be getting a barrel longer than 18" so I am not sure how much benefit I would get there. You can also form the brass from 7.62x39, which is a huge plus. There is cheap wolf ammo out there for it, and it seems to be a niche, but growing niche caliber. On the minus side, bullets and brass are more expensive, and I hear there are some struggles with feeding.

6.8 has better velocity out of a short 16" barrel, might feed better, brass and bullets are cheaper, and I already have 90 pieces of range brass. and it would be simple to rebarrel to 224 valkyrie if that caliber ever takes off or proves to be a viable hunting round. On the minus side, it has shorter legs, seems to be waning in popularity, factory ammo is expensive, and barrels are harder to find.

does anybody have strong opinions or experience with either caliber? I will eventually be hanging a suppressor on it as well, which is why I want to keep the barrel length on the short size.

 

[LoonWulf]

Feeding can be an issue with Grendel in larger magazines. I only ran 10 rounders and i notched the fronts to get a longer coal on for my Grendels, so i only loaded 5-7s. I never had a failure of any sort with both of my uppers.
With the shorter barrel id probably go with the 6.8. I think the Grendel is best served with a 20+
Having hunted with the Grendel, the .223/5.56, and my 6X47 quite a bit, I Honestly i think 300-350yds is about as far as I would be comfortable shooting at live game in the 100-150lb range with anything that fits in a Ar-15 using standard parts. Even our 40-60lb feral goats have eaten a good hit from my 6x47 at 250-300 and run off like they were fine.
Not saying you cant, or even shouldnt do it, but its not something I would be comfortable with.

 

[marksman13]

I have shot a bunch of pigs and deer with a 6.8 SPC. It is one of my favorite cartridges ever designed for the AR-15 platform. It will reliably kill large pigs out to 300 yards and probably further though I've never attempted a shot any further with my 6.8s. I will always own an AR-15 chambered in 6.8, period.

That said, I am putting parts together for a 6.5 Grendel now. The Grendel is superior to the 6.8 when the range extends past 400 yards. For punching holes in paper or shooting an antelope at extended ranges, the Grendel is just ballistically better. I can't really say that I need a 6.5G, but I am building one anyway because I like what the cartridge brings to the table.

If I'm honest with myself, the 6.5 Grendel is probably the way to go if you are in an either/or situation. The 6.8 has the benefit of ammo availability and higher velocities from shorter barrels, but the 6.5 Grendel sounds better suited for your needs overall.

 

[Varminterror]

From their inceptions through about 3 years ago, I would have recommended the 6.8 over the Grendel. The availabilities of each has flip flopped, such I’d be leaning towards the Grendel. Will that change again in the future? Eh, probably not, as there are broader options for Grendel rifles and extreme popularity in other 6.5mm cartridges to bolster the bullet supply and keep it tipped in favor of the Grendel long term.

I have a 20” Grendel, plus SPC’s in 18” and 10.5”, my Grendel is built for long range steel banging, the SPC’s are built for hunting, one suppressed, one loud. At 600, there’s really not much difference, once I give my 18” SPC sufficient support (hand guard and weight just isn’t made for long range work so it needs a little help).

So at worst, it’s a coin flip. I get a little more speed from the SPC, but suffer a little on BC and beg for suitable bullets.

 

[boom boom]

You can get good performance from both. I decided upon the 6.8 SPC simply because there is more and better hunting ammunition off the shelf at some of your larger sporting good retailers. Not so much for the Grendel right now unless you handload. However, ammo via the internet is only a couple of clicks away.

The 6.8 also works better in a shorter barrel which is what it was designed to use. Paper punching, flip a coin until you get pretty far out. One thing, Starline brass is now making 6.5 Grendel brass as well as 6.8 SPC.

 

[boom boom]

I'm going to rebarrel my ar. I'm leaning toward either the 6.5 grendel or the 6.8 spc. It is going to mostly punch paper, and I'd like it to do MOA or better with my handloads, but also spend time hunting hogs at 50-175 yds. It would also be nice to be able to strtech out to 500 in a pinch to take a shot at an antelope. but that would be very infrequent. Basically I want something with longer legs and more punch than a 223 without buying a new AR in 308.

6.5 grendel is theoretically a better long range gun, but I would not be getting a barrel longer than 18" so I am not sure how much benefit I would get there. You can also form the brass from 7.62x39, which is a huge plus. There is cheap wolf ammo out there for it, and it seems to be a niche, but growing niche caliber. On the minus side, bullets and brass are more expensive, and I hear there are some struggles with feeding.

6.8 has better velocity out of a short 16" barrel, might feed better, brass and bullets are cheaper, and I already have 90 pieces of range brass. and it would be simple to rebarrel to 224 valkyrie if that caliber ever takes off or proves to be a viable hunting round. On the minus side, it has shorter legs, seems to be waning in popularity, factory ammo is expensive, and barrels are harder to find.

does anybody have strong opinions or experience with either caliber? I will eventually be hanging a suppressor on it as well, which is why I want to keep the barrel length on the short size.

On barrels, try primary arms unless you are wanting match grade.

 

[SharpDog]

I'm going to rebarrel my ar. I'm leaning toward either the 6.5 grendel or the 6.8 spc. It is going to mostly punch paper, and I'd like it to do MOA or better with my handloads, but also spend time hunting hogs at 50-175 yds. It would also be nice to be able to strtech out to 500 in a pinch to take a shot at an antelope. but that would be very infrequent. Basically I want something with longer legs and more punch than a 223 without buying a new AR in 308.

6.5 grendel is theoretically a better long range gun, but I would not be getting a barrel longer than 18" so I am not sure how much benefit I would get there. You can also form the brass from 7.62x39, which is a huge plus. There is cheap wolf ammo out there for it, and it seems to be a niche, but growing niche caliber. On the minus side, bullets and brass are more expensive, and I hear there are some struggles with feeding.

6.8 has better velocity out of a short 16" barrel, might feed better, brass and bullets are cheaper, and I already have 90 pieces of range brass. and it would be simple to rebarrel to 224 valkyrie if that caliber ever takes off or proves to be a viable hunting round. On the minus side, it has shorter legs, seems to be waning in popularity, factory ammo is expensive, and barrels are harder to find.

does anybody have strong opinions or experience with either caliber? I will eventually be hanging a suppressor on it as well, which is why I want to keep the barrel length on the short size.

I went 6.5 with an 18" bbl. Having my upper built (I wanted cerakote camo) for my DDM4V7LW and have not received it yet. My use will be hunting at the same ranges you specified, maybe a tad longer. This rifle will be a lightweight hunter. Already have a 7.62x39 for CQB. If I need a longer range rifle I will get another upper (with a 20" bbl) for my Les Baer AR.

Pluses as far as I see it
1. Really, really good at longer ranges, perfectly fine at shorter ranges.
2. Ammo is very cheap (less than 0.28 per round).

The only negative is that the cheap ammo limits barrel life to 4K rds and is only accurate to 2 moa. To get better accuracy ammo cost goes to 0.75 per rd.

The main negatives I see for 6.8 SPC II are that it is:
1. waning in popularity
2. not as versatile as the 6.5G

 

[greyling22]

I suppose either would work, and spc would probably fit my needs better, but if parts availability is anything to go by, Grendel is vastly more popular. I guess I will go that way.

There seem to be 2 categories of 6.5 barrels. Bear Creek for under 100, and everybody else for 200+. (Faxon, Alexander arms, etc)

Has anybody tried the bear Creek ones? Are they accurate?

 

[dh1633pm]

I went with the 6.8 in the Ruger Mini platform. Paid what it costs to make it my own. I can't say what the future holds, but for a shorter barreled carbine, the 6.8 is a deer killing round that should be around a long time.