6.8 v 6.5G v .300BLK

Thinking about an additional upper, for deer out to 200. 6.8 seems to be the best compromise of off-the-shelf ammo vs ballistic capability, although with .300 you have the subs possibility. 6.5 is obviously the most powerful but has limited ammo options, and I can always pull out the bolt actions in 7mm-08 or .308 at that point. What say ye?

I am partial to the 300 blk. I haven't shot the other rounds so I cannot offer a comparison.
One thing I like about it is the use of standard AR mags. There is a wide range of projectile possibilities from 110 to over 200 grains.

Mine has taken many pigs and a couple of coyotes.

Big fan of the 6.8 caliber and believe it is the best hunting caliber on the AR platform. The 6.8 is neck and neck with the Grendal until about 300 yards, at that point the grendal has the edge. That being said the 6.8 has a wider range of bullet options and ammo availability. Next is the 300BO, all I will say is I have friends and customers that bought into the 300 hype for hogs and shortly after that sold them for a 6.8. I personally don't own a 300BO so only speaking from my experiences with other people. I have killed hundreds of pigs with the 6.8 and if you search other forums about hog hunting the 6.8 is the highest percentage caliber used.

If you ain't runnin a can I see no use for the 300BO. 6.8 all the way!

Simple reason I love the .300 Blackout. Hits pretty damn hard with Barnes Vor-TX 110gr at ranges less than 150yds and recoils like a .223/5.56. Also my AAC MPW is pretty damn accurate.

Most of my shots are within that range and my 8yr old son can use it with ease. Win, win.

I am in the same debate... I have a 300 BO that i will use for hogs inside 100 yards.

I wanted an extra upper for deer rifle back up. The 6.5 has the better bullets but the 6.8 has the better availability. If the 6.8 had the AMAX bullet i would be game. But all there is is hunting bullets.

If you want to shoot quiet and have a can, then I'd say go 300blk. Especially go that route if you are going with a short SBR. My SBR 300blk with a can attached is shorter than a 16" rifle.
If you don't have a can, then the 6.8 is a sweet shooting low recoil round.
I've never shot the 6.5G.

I've never had a problem shooting deer or pigs with the 300blk. Out to 200 yards, any of the rifles will work fine. So I would look at availability of the upper/barrel you want and cost/availability of ammo.

Info I got from Barnes and Hornady that compares the 2 calibers. The ammunition used is the Barnes 300BO 110r TAC-TX and in the 6.8 it's the Hornady 120gr SST. Both rounds seem to be the go to ammo for both calibers, offering some of the best performing for each caliber.

300BO______Muzzle____100 yards____200 yards____300 yards____400 yards
Trajectory____-1.5_________0__________-6.7_________-24__________-55.5
Velocity______2350_______2070_______1810________1574__________1369
Energy_______1349_______1046________800_________606__________458

6.8_________Muzzle____100 yards____200 yards____300 yards____400 yards
Trajectory____-2.40________2.2__________0__________10.5_________31.1
Velocity______2460_______2250________2050_________1862________1685
Energy_______1612_______1349________1120_________923__________756

As you can see the 6.8 has less drop than the 300 BO. At 100 yards it has 8% more velocity and 200 yards it has roughly 12% more. At 100 yards the 6.8 has 22% more energy and at 200 yards it becomes roughly 28% more than the 300BO. Pretty cut and dry!!

This data came from the ammo manufactures website.

24 inch barrel. 6.5 Grendel 123gr SST From Hornady website , A-max also available
Velocity (fps) / Energy (ft-lbs)
MUZZLE____________100__________ 200____________ 300____________ 400_____________500
-2.40__________ 1.80___________ 0.00___________ -8.70__________ -25.30_________ -51.30
2580/1818______ 2410/1586______ 2247/1379______ 2090/1193______ 1940/1028______ 1796/881

Rifle (16" Barrel) Velocity (fps) / Energy (ft-lbs)
MUZZLE_________ 100____________ 200____________ 300____________ 400____________ 500
2350/1508______ 2189/1308______ 2034/1129______ 1885/971_______ 1744/831_______ 1612/709

Apples and oranges. Why aren't you comparing a 110g 300blk bullet to a 110g 6.8 bullet? It's a bigger lighter bullet, of course it's going to be much different. Velocity difference means squat at those speeds and 200 yards. As long as it's enough to expand the bullet with good penetration, what does it matter? A 4.5" difference in drop at 200 yards... not going to matter if you are practiced with your rifle and know the drop. And look at the Trajectory of the 6.8. How does a bullet go from hitting 2.4" high at the barrel, to 2.2" low, to zero, and then to 10.5" low? Isn't that a big 'W' flight pattern? Something isn't right there.
Anyway, if you base all your purchases on numbers on a piece of paper, then you should only be hunting with a 50 BMG because its numbers blow away most other rifles. Pretty cut and dry.

Your numbers came from a 24" barrel, not a 16" like the others. So lets compare apples to apples
MUZZLE____________100__________ 200____________ 300____________ 400
2350/1508______ 2189/1308______ 2034/1129______ 1885/971______ 1744/831

That makes the 6.8 outperform the Grendal to about 200 yards. After 200 yards the Grendal slowly pulls away

I was just putting information out therefor the OP. Energy on target is energy on target!!! I used those 2 bullets because they are supposed to be one on the most effective. Here is a 110 gr Hornady V-max and it still has more energy on target than the 300BO!!

6.8 110 gr Hornady V-max
Barrel (16") Velocity (fps) / Energy (ft-lbs)
MUZZLE -------------100 ----------200 ---------300 ------400
2550/1588---------2319/1313-------2100/1077------1893/875----1700/706

I have a 6.8 and 300 BLK. The 6.8 is a little better as 200 yds is close to max for the 300B. But when in doubt get both! The 300B is a beast at close range!

Considering 200 ft/lb of energy will kill a deer or pig, the difference in energy between all 3 rounds in 200 yards is pointless.

i prefer grapenuts

I have the blackout and the 6.8 the blackout stays in the safe now. Compared to the 6.8 the blackout was underperforming on hogs, I don't know about all the numbers just real word experience. Will a blackout kill hogs yes it is the ballistic equivalent of a 30/30. The 6.5 is nice also but I feel the 6.8 will be more commercially available.

So between the three my choices would be 1) 6.8. 2) 6.5 3) 300bo. They will all kill hogs with proper shot placement some provide more room for error than others. Only reason I can see to chose the BO is cost.

It's actually pretty simple. 300 black if you're going to do an sbr and suppress it for short range hunting. If not that scenario then grendel and 6.8. 300 is a very specific gun. For me it is perfect though for my hunting scenario which is night vision and suppressed at less than a hundred yards at night. In distances further than that the 300 sucks. I have two of them and love them but for what you're wanting I think you'll happier with the 6.8. The 300 will bring down huge hogs but shot placement is key just as it is with any other round on a big tough plated hog.

MDMorrow, I agree with you on the 300 BO working well out of SBR's and short distances but the 6.8 performs well out of a SBR also. Where as the 300 BO is good down to +/- 8" the 6.8 does really well at 12.5" and up.

Get a 6.8 and a 300BO. You can never have too many choices! Oh, and a 458 socom too!

Stop muddying the waters with scientific data!

Ballistic coefficient paired with muzzle velocity, yeilding more retained velocity and energy is not welcome here!

I should have clarified. 8.2" noveskes are what I run for a couple reasons. The shorter and lighter the better as most of my hunting involves thermal spotting then stalk up to take the shot. We have a lot of cows so getting up closer for positive ID is a necessity as is a lightweight rifle since a lot of walking is involved. If I was shooting for a longer distance I'd be using something in a large bore AR platform. I had a JP but found I never used it since my chances of a nighttime distance shot on our place is rare.

Muddying with scientific data?? Lmao. Its performance info off the manufactures website. OP asked a question so I put information out there so they would have info available to choose. No charts or graphs from a program or coefficients. Posted the stuff I looked at when I was deciding on a larger caliber for hunting hogs. If it bothers some folks, don't read it.

Sarcasm detector must be broken.

Well, I have 2 300 Blackouts, 1 10"SBR, and 1 16". I also have a 20" Grendel, and a .50 Beowulf. I don't own a 6.8, and I don't plan on owning one.
But I don't like .270s. (.277) or (6.8) but that is my choice! But I like .264 bullets, and .308 bullets.
But, that's why they make so many calibers.

My post with your post quoted was also from Hornady site. You had just left out the one of those 3 cartridges I like best. So I added it.




How true

Must be...

Yep!!! Must be. I have been part of THF for a while but haven't really been on here in some time. I don't know the flow of this forum like I used to.

That was my bad and not intentional. I got distracted and hit post before I got it all together.

Different calibers for different missions. I love that I can use all my 5.56 components on my 300BO. With a mag change on can from subs to 110TSX that are PFM. If I did not care about sub/SBR/CQB I would go with 6.8

Thanks, gents. I figured 6.8 was the way to go since this will just be an additional upper, I won't be multi-hog hunting, and I want to find ammo off the shelf. If I was going to go 6.5 I'd build an entire AR for it so that I could really use the whole range of the cartridge. I wouldn't doubt that eventually a .300 joins the fold, though! Geez, I'm going to have to get a second job or win the lottery....

I am a big fan of the 6.8, have been for about 6 years.
FWIW, I have ran about all the ammo for it and handloaded a bunch.
I was running the 95g TTSX for the longest time and Hornady sent me a batch of the factory 120SST ammo.
It flat out works.
I have seen it around Austin and at least around here there are more 6.8 ammo choices than 300 blackout.
That doesn't mean what's in stock at the moment either.

They all work of course.

Just do a ptr pdw sbr...

That will have enough firepower

If I ever run out of Accubond the SST is what I will probably switch to. No complaints on the Accubond other than I can't get them locally. The SST has always impressed me in other calibers anyway.

just depends on what all you want to buy, .300BLK everything is the same except the barrel. I've ran my 8" .300BLK to 250yds no problem. its really your personal preference between all 3...

and can we please get an NFA sticky thread and apparently we need a .300BLK/6.8/6.5 sticky thread too...

I have a 6.8 and love it. I've shot several deer and a few pigs and never lost one. It's very accurate and predictable. I've had a few friends who have switched to it as their primary rifle after seeing how well mine was doing.

I keep seeing this posted but a 300 no is not the equivalent of a 30-30. 110 bo has the sam velocity as a 150 gr 30-30. Both are good rounds for what they do but they are not the same.

Using 1680 powder, you can load 150g 300blk to 2000 fps, same as 150g 30-30. You can even use the same Interlock bullet in the 300blk. You can load 110 g bullets in both to 2200 fps, but the 300blk uses about half the volume of powder.

Check your numbers, those are selling the old 30-30 short by easily 200 fps from a 20 inch barrel

Tell that to hornady. It's their numbers.

The data I used is also from Hornady

Hornady 30-30 factory ammo





Even with 13000 psi more pressure spec for the blackout it lacks the case volume to catch the old 30-30.

To be fair that 30-30 data is out of a 24in barrel, most of the data i have seen for 300BO is 16in

That bottom one is 150 @ 2100 fps 24In
Chad has 300BO ammo that is 150 @ 1950 fps 16in.

Yes the 30-30 does have more fps but its not apples to apples.


The big game changer for the 30-30 was the Lever Evolution gunpowder. That kicks the 160 grain up to 2400 fps

That bottom one is the Custom Lite reduced recoil load. Before I made the first post about the comparison I had run the fastest loads I could find through quickload and that is where I came up with about 200fps difference. That appears to hold true at 16 inch barrel or 20 inch barrel which are more realistic of the real world barrel lengths.

good call didn't read that it was reduced load...but the 16 vs 24 is still true

the 30-30 does have more power than the 300BO not arguing that.

But i would prefer a sbr 300 bo to a 24 in 30-30

My numbers were from Hornady 9th Edition, 16" 300blk vs 20" 30-30.

I've been shooting 140 gr Berger VLDs in my 6.8 AR and am very impressed with the performance. They can be loaded to magazine length. 2400 fps out of a 16" barrel and retains enough energy to drop hogs pretty convincingly out to 300 yards. Reportedly supersonic out to 1000 as well.

IMO, .300BLK if you want to run a can, 6.8 if not.

SBR - Blackout
With a Can - Blackout
No Can and sub 300yds - 6.8
No can and 300+ - Grendel

Personally, I'd get a LWRC Six8 UCIW and a Specwar 7.62 and run 90gr Gold dots. Then you have the best of all worlds all the way to 200yds.

I've owned all 3 calibers, 95% of my shot opportunities for hunting environments are less than 100yds. I'm currently running a SBR Blackout.

I don't own either of these calibers but why not a Grendal with a can? The 6.5 seems to have better ballistics beyond 200 yards. I've been thinking of buying my daughter an AR hog/deer rifle which is lighter than her 270 and add a can. Probably NV or Thermal.

With Thermal, it will be mine .

Why BLK with a can-isn't the can good with any of them?

Because the blackout can shoot heavy rounds at subsonic speeds so it's quiet through a can. I think there's 6.8 subs off the shelf, but the bullet is light weight. Use the can with all 3 if you have a can. But it will be by far the quietest with 300 blk subs.

Yep, heavier bullet at the same velocity means more energy.

But energy increases exponentially with velocity. Way more effective than just increasing the weight.

Subsonics are subperformers.

I have several 300 BO and 6.8s. I've also toyed with the idea of a 6.5 for a long time, but still. haven't pulled the trigger.

6.8 is the best round for deer/pigs under 300, period. If I was hunting antelope, I might add a 6.5 to the herd. As it now stands, if the antelope opportunity arises, I have a few 308s that'll do the job.

300 is flexible. It's a great CQB weapon, and a good for under 150 deer/hogs with supers. While subs are quiet, and many hunt with them, I still haven't found a bullet that I like for hunting with it. And the reason for that is that I almost always just grab a 6.8 for hunting.

Ragerding cans, there's a lot of noise about them being useless with supers; to which I reply "hogwash". When I stick a can on my 6.8, it's comfortable to shoot without hearing protection. I haven't stuck a mic next to it to see how many DBs it's pumping out and whether it's actually hearing safe, but my ears say that it is. My 11.3" 6.8 SBR with a Saker 762 is pretty much my go-to field combo, nowadays.

True that 6.8 brass is more expensive than 300, but I just ponied up and bought 1,000 pieces of once-fired federal for about $180. This, along with the 1,000 or so pieces I had from miscellaneous other stuff, and I've pretty much got hunting brass for life. Bullets are very easy to come by and there are some excellent hunting pills out there.

But I still like my 300s. I have a 9" SBR, a 10.5" SBR, and a 16". All are wearing an AAC 51t mount, so that they can share an SDN-6. And all are fun to shoot.

If longer range is your thing, the 6.5g may be interesting. But for me, the brass is just way to hard to find, and expensive to buy. The bolts are problematic, with many horror stories of bolts breaking. There's confusion as to whether the chamber specs will be changed again. 6.5 needs long barrels to shine, and I like SBRs. And with most loads, my 6.8 is just better under 250-300.

If I still lived in Montana, where there are lots of 300+ opportunities, you can believe I'd have a 6.5g.

Nice post, WhoDat. Thanks!

well put and I agree 100%
Shooting supersonics I can't detect a difference out of the same barrel length with the same can.