This is not intended to be a 6.8 vs 6.5 (Grendel) thread. I’ve lurked all over the web and watched nearly every YouTube video there is on that subject. In an effort to make my final decision between the two I am going to let ammo availability and cost be a big factor. With that out of the way, here are my main questions.

6.8 seems to be less expensive, unless you consider the steel cased Wolf 6.5 (which I’m not excited about).

I buy nearly all my ammo online, so local availability isn’t a deal breaker.

Finally, am I remembering correctly that the Army finally picked a new rifle chambered in 6.8 to replace the M4, etc? What do y’all think this will do to 6.8 ammo pricing? https://www.tactical-life.com/...-8mm-weapon-systems/

I guess there aren’t many questions in this post.. just thinking out loud. Opinions on cost/availability of the two?

I've been thinking about the two periodically myself, and a quick look around tells me the same thing I've been hearing over the last few months. 6.8 is marginally cheaper and tends to offer marginally more options in general just because of the S&B and PPU offerings (brass cased, good quality ammo IME in other chamberings), whereas there seem to be a couple more options in factory-loaded hunting ammo for the 6.5 Grendel. There really doesn't seem to be that big a difference to me, though. PPU may come up with some more Grendel options down the line just because the Serbia Army is in the process of shifting over to rifles chambered for it.

FWIW, I'm not sure the Army's looking at the 6.8 we all know and love so much as a new cartridge firing a .277" bullet.

I guess a big part of my thinking (or confusion) is wondering what effect the military adoption of 6.8 will have.?? Is that too far down the road to consider? Still cased Wolf Grendel ammo is cheap. I doubt I’d ever shoot it though, not a fan.

Again, what do you intend to use the rifle for? Start with this. If you don't understand your purpose for a new rifle/upper, you could be spending money without tangible benefits.

I'll assume you already have AR-15s in 223 or 5.56.

If you're shooting targets -- paper or steel -- out to 300 or 400 yards, neither 6.5 nor 6.8 will provide any tangible advantage over good 223 match ammo.

If you're looking to maximize kinetic energy on target -- especially on a short-ish barrel -- both the 6.5 and the 6.8 will provide a tangible advantage over 223. This is a combination of larger powder capacity and the physics effects of a larger bore. Physics students, plumbers, and HVAC engineers know this from the properties of fluid dynamics.

6.5 and 6.8 make sense for hunting applications, both from the higher energy on target and the larger bore size -- which can be a requirement with some state's game laws.

Both 6.5 and 6.8 have reduced magazine capacity in comparison to 223. Both 6.5 and 6.8 can have issues feeding ammo from their magazines. Both 6.5 and 6.8 are harder on their bolts than 223. Both 6.5 and 6.8 will have longer barrel life than 223 -- but unless you're retiring 223 barrels due to throat erosion, this isn't a factor.

Factory 6.8 ammo tends to have MV and KE data calculated from 16-18" barrels. Factory 6.5 ammo tends to have MV and KE data calculated from 20-24" barrels. As a result, stated 6.5 data is often higher than 6.8 data.

6.5 promotions often show drift data with 123 grain match bullets. Yeah, the drift numbers look good, but MV for this bullet weight is pretty low. Honestly, I think 123 grain is too heavy for the boiler room in a 6.5 case. IMO this is one reason 6.5 target shooters use long barrels to squeeze every bit of MV from the cartridge.

6.8 has a noted following with hog hunters. It appears there have been good hunting bullets in factory ammo for quite awhile.

6.5 completely rules over 6.8 in precision/steel/tactical carbine competitions. With some of the newer factory loads with 6.8 match bullets, this may -- or may not -- change over time.

This message has been edited. Last edited by: fritz,

Good points, Il Cattivo... and Fritz!

I recently bought an 18” Grendel Upper from PSA. If just wanting to pin the upper on whatever lower, the Grendel seems simpler. I thought there was an extra requirement for the 6.8.

I see either ammo at a few of the larger sporting stores. I add a bit with mail orders, then reload most I shoot.

I have several Grendel specific magazines, feeding has been pretty good, not 100% infallible quite yet though. I only have a few sessions shooting it so far, evaluating some reloads.

There is a Grendel dedicated forum, though to much time there will swing one towards getting a 6.5.

Starline makes brass for both calibers. Now might be a really good time to start reloading whichever choice you eventually make. Unless you plan to do a lot of frivolous blasting, you don’t need an expensive progressive press set up. You can load exactly what you want to shoot, and eventually shoot cheaper than factory.

Smart advice concerning the reloading. It’s been on the back burner for some time now, eventually I’ll get involved in it. Biggest problem right now is that I have no where to set up a bench... but that’s a story for another thread. Honestly I think I’m leaning Grendel, I just want my cake and be able to eat it too (cheap available ammo)!

dagnabbit -- messed up my first post with an edit from a second time.....

No worries Fritz, I’m following along. You’re right, I do have a couple of 5.56 AR’s already. My goals for this gun are: fun/want, hogs, steel/paper at distance. How far, honestly I don’t know yet. I’ve never gotten involved in long range shooting before... but would like to. I’m limited to under 400yds by the closest ranges currently. I kinda am getting the impression that 6.8 will fill my role, but Grendel will plus some.

Edit: I’d also like to stick to a 16 or 18” gun.

quote:

Finally, am I remembering correctly that the Army finally picked a new rifle chambered in 6.8 to replace the M4, etc? What do y’all think this will do to 6.8 ammo pricing? https://www.tactical-life.com/...-8mm-weapon-systems/

I wouldn't make any decisions based on a military announcement on a M-4 replacement. They have announced and cancelled this many times since 9/11. Maybe this will be the one that isn't cancelled, but I'm not holding my breath.

Personally, I went with Grendel. I have 20" rifle and a 12" pistol in it. For the first time in my life I've purchased Wolf ammo, but haven't shot it yet.

quote:

Originally posted by dry-fly:
No worries Fritz, I’m following along. You’re right, I do have a couple of 5.56 AR’s already. My goals for this gun are: fun/want, hogs, steel/paper at distance. How far, honestly I don’t know yet. I’ve never gotten involved in long range shooting before... but would like to. I’m limited to under 400yds by the closest ranges currently. I kinda am getting the impression that 6.8 will fill my role, but Grendel will plus some.

Edit: I’d also like to stick to a 16 or 18” gun.

With a 16-18" barrel you won't see a whole lot of muzzle energy differences between the two calibers. I seem to recall that the 6.5 has just a touch more powder capacity, but the 6.8 will bring the bullet up to speed a little faster due to its slightly larger bore. Use comparable hunting bullets and either caliber will work on hogs.

As I stated, for steel and paper targets out to 400 yards you really won't see any tangible advantage to 6.8 or 6.5. It's quite possible that a good load in your 223 will perform better.

Beyond 400 yards on paper/steel the 6.5 holds the advantage over 6.8, as its 123 grain match bullets are more slippery in the wind. If bullet manufacturers develop a comparably weighted 6.8 match bullet, the 6.5's advantage at distance will narrow noticeably.

Target shooting with ARs is a discipline all its own. By comparison, bolt action rifles are easy to shoot accurately. Many shooters are frustrated that they can't obtain consistent precision with AR-15s, then write them off as finicky, inaccurate, POS contraptions. Understand that few people can truly shoot an AR accurately at 100 yards. Increase the distance to 400 yards and the list gets smaller. Increase to distance again to 500, 600, and beyond and the groups dwindles big time.

As a result, many AR owners bang away at close distances, or use relatively big pieces of unpainted steel at longer distances. Unpainted steel means the shooter can't track the location of his impacts -- nor can observers around the shooter. Easier on the ego this way....

Not long ago I ran the numbers on my primary competition 223 AR-15 versus some other calibers. Primarily 224 Valkyrie, but also 6.5 Grendel.

Using factory ammo (Hornady 73 ELD-M vs. Hornady 123 ELD-M), with comparable rifles, at my altitude:

400 yards
223 bullet drops 24.8" and drifts 10.8" in a 10 mph cross wind
6.5 bullet drops 31.6" and drifts 10.0"

600 yards
223 drops 77.4" drifts 26.4"
6.5 drops 93.0" drifts 23.4"

From this analysis, for my type of precision/tactical/steel matches, I decided switching from 223 to 6.5 wasn't worth it. But again, this is for target use only.

Interesting, thanks again fritz.

quote:

Originally posted by fritz:
Not long ago I ran the numbers on my primary competition 223 AR-15 versus some other calibers. Primarily 224 Valkyrie, but also 6.5 Grendel.

Using factory ammo (Hornady 73 ELD-M vs. Hornady 123 ELD-M), with comparable rifles, at my altitude:

400 yards
223 bullet drops 24.8" and drifts 10.8" in a 10 mph cross wind
6.5 bullet drops 31.6" and drifts 10.0"

600 yards
223 drops 77.4" drifts 26.4"
6.5 drops 93.0" drifts 23.4"

From this analysis, for my type of precision/tactical/steel matches, I decided switching from 223 to 6.5 wasn't worth it. But again, this is for target use only.

I did the same thing a little over a year ago.

I went with 223 as you know because my criteria didn't require energy.



Between 6.8 and 6.5 Grendel I personally see little reason to choose the 6.8 But that doesn't mean there is anything wrong with the 6.8. I just favor the additional long range attributes of the Grendel.

^^ Yeah, but do those attributes really exist with anything shorter than a 24" barrel? All I "know" is what I've read on the subject, but bullets from both cartridges seem to be traveling pretty slow at 400 yards from a 16" barrel.

I’m clearly no expert on the rounds, but I’m seeing a fair little bit of NFA Grendel items. There’s a section on them over on the Grendel forum. Obviously a longerbarrel may yield optimal results, but I think it’s got plenty of lunch still from a 16” barrel.

quote:

Originally posted by Il Cattivo:
^^ Yeah, but do those attributes really exist with anything shorter than a 24" barrel? All I "know" is what I've read on the subject, but bullets from both cartridges seem to be traveling pretty slow at 400 yards from a 16" barrel.

I used real-world numbers from my own 20" barrel 223. I gave my best shot at muzzle velocity for a 20" barrel Grendel, based on what people report for factory ammo on various barrel lengths. I don't recall if there was a "ballistics by the inch" type test for the Grendel, where people cut a long barrel down inch-by-inch. I do see other competitors with Grendels in team competitions, and I try to ask them for data on their rigs. So I know the ballpark numbers.

Changing the barrel lengths from 20" to 16" will have some affect on the numbers, which should make 6.5 look a little bit better in comparison to 223.

At 400 yards my 73 grain ELDM is chugging along at 2,112 fps from the 20" barrel. Not exactly a speed demon, but still at Mach 1.89. I didn't keep velocity data for the other cartridges, just drop and drift figures.

I had this conundrum about a year ago. A buddy and I each bought a lower and were toying with different calibers to build...to have something "different". After a bunch of research I went with the Grendel.

My goal was to build out a 16" handy AR deer rifle (in my state the caliber must be .243 or above to be deer legal). I got suckered in by the energy retention of the round. In hindsight, I wish I'd gone 6.8...or .300 Blackout....or just built another .223 and stuck to lever-actions for deer.

Grendel brass is expensive. Bullets are hard to find locally, as is loaded ammo. The Grendel loses a lot from the shorter barrel, and the el-cheapo bear creek arsenal barrel I bought won't group to save its life. And who am I kidding...I'm not going to take shots at deer at 400+ yards anyway.

The gun doesn't get shot much because it isn't accurate, and being an AR it isn't easy on brass....and did I mention Grendel brass is expensive?!?!

So I'm now debating...do I buy a new (better) barrel for it in 6.5 Grendel...probably a longer one this time with a rifle-length gas system....and turn it into a paper puncher/less handy deer rifle? Or do I sell the upper, all my brass and dies, and build a different upper in a caliber that's more economical/appropriate for my uses?

quote:

Originally posted by 92fstech:
In hindsight, I wish I'd gone 6.8...or .300 Blackout....or just built another .223 and stuck to lever-actions for deer.

the el-cheapo bear creek arsenal barrel I bought won't group to save its life.
The gun doesn't get shot much because it isn't accurate

So I'm now debating...do I buy a new (better) barrel for it in 6.5 Grendel...probably a longer one this time with a rifle-length gas system....

A barrel is the heart of a firearm. A cheap barrel is a huge gamble in a rifle's performance, and it appears your gamble wasn't good. A quality barrel -- and the accuracy it produces -- makes a rifle more enjoyable to shoot.

If you stay with a 16" barrel, the practical short-range deer hunting utility of a 6.8 SPC or 300blk will be little different than with a 6.5 Grendel.