If you want to shoot past 400 yards AND are willing to reload, yes indeed.  The 6.5 BRX is a great cartridge.  I have found that my non-556 ARs are mainly used around hunting season and for target shooting at long ranges.  So reloading is not an issue for me as volume is low.

/thread

I appreciate the honorable mention, and yes, we have a ways to go with the .277 Wolverine but I wouldn't call it "long".  Come June it will be down to "a little ways to go".

That being said even though I developed my own cartridge I don't have cartridge envy, cartridge insecurity, or whatever the issue always seems to be.

OP, I would suggest the 'ole pros and cons list on paper, and then actual research rather than asking opinions from a few very opinionated people. Most of the folks around here are great, and some will take to their corners and come back swinging.

The above statement is not pointed at anyone in particular here.  There is a ton of great knowledge here but if you sit at a bar and ask a group of guys "blond, brunette or red head", "chevy, ford or whatever", expect the same responses.

To add to the technical part of this discussion I will say that if you use your intended use pros and cons list, cross check that with ballistic data, cross check that with parts and components availability and cost, you will get your answer.

Nope,, not yet. Huh,I'll be dern. $100 for 1000. cases.
I was talking about cutting down .223, not factory 300 brass.
I just said there was a factory subsonic for the 6.8 & the Bison platform.. I did not say the 6.8 was as good as the 300BO(Whisper) at subsonic shooting. Which it clearly is. Yes, 99% of 6.8 ammo is supersonic. It is not it's forte`. So, no real argument there.

Really the 6.8 is mainly a General Purpose Cartridge. Not great at subsonic, or have really great match high BC for long distance(600+ yards) of the Grendel. But, it will do both, just not as well.
(Goldilocks approved, LOL)


All the alternative AR Calibers have their pros & cons, They are true alternatives to the .223/5.56. Allot of development & experimentation involved, (Mainly in the top 3 non-pistol cal. alternatives 6.5G/.264 LBC, 6.8 SPC & 300 Blk). All 3 will kill a Whitetail Deer within the 200y the common Eastern deer hunter's range.

PS I am disappointment no one wanted to see the HWC TV & Archer's paradox videos. LOL!

Blocked from the forum...VA-gunnut

even more confusion.

But as another said buy which ever you will eventually build another AR.

PRI 6.8 mags cheap.

Until this thread I didnt know anyone even thought the 300 BO was competition for the 6.8.


It does not reach enough speed for me to consider it for anything but a sub.


Interesting
 

Thats alot more than a little case prep if you want to shoot any numbers.
I hate trimming let alone those steps in any quantity.

This is actually one of the main reasons I stayed out of the 6.8 game.  I hate metal mags and they always make a lot of noise when hunting with them.  

If the 6.8 is the best thing since slice bread then why doesn't Magpul make mags for it?

They do.  but they only fit in the lwrc 6.8 recievers

https://www.lwrci.com/p-354-magpul-pmag-six8.aspx

From what I understand it's the magazine stack angle.
The thicker walls of a Magpul plastic magazine cause the stack angle to be more severe.
This can cause feeding issues.
For this reason Magpul will not make a plastic magazine for any of the cases fatter than the .223/5.56. (in an AR15)
They cannot insure it would feed with total reliability.


This is why LWRC created the Six8 when the contract with the Arab states called for P-Mags.
The mag well is wider to accommodate the thicker plastic of the P-mag.

FYI the PRI mags are solid welded not spot welded and as such are very strong and made to a higher degree of precision.
I have mags for my 6.8 from CPD, ASC and PRI. The only ones I have ever heard rattle that I own are the CPD's.

As by now you all know I have a passion for the 6.8SPCII, I do not think it's the best thing since sliced bread.
I do however think it's the best all around variant in an AR15.
There are others that do certain things better, but it can do all things well.

I have never had a mag rattle in my 6.8.

OK, the old C Products did rattle if I didn't tap the back of the mag on my hand or something. The CPDs I had didn't. The Barretts didn't. The PRIs don't. I'm assuming you're talking about ammo in the mag.

Lot's of my .223 metal mags have rattled.

If mag to magwell, None of my 6.8 mags rattled, though I never tried them in any receiver but the one. With Aluminum .223 mags, some do, some don't, it varies between receiver and mag, but really not rattle per se, more of a looser fit in some, but still a solid fit.

Except subsonic

Yes, if you prep your own 300 BLK brass, you will need to cut, size, trim.

But that's a one time deal.  After that it's no different than reloading 6.8, 6.5, 223, etc.  Size and trim like every other cartridge.

OP, if I was to build another 6.8 sometime down the road.  I'd lean towards something in the 10.5"-12.5" range.



ps. Or you could purchase prepped 300BLK brass from a reputable seller for relatively cheap.

ymmv

Read the above a bit more carefully.
We were talking about the 6.5 BRX from AR Performance and the case work and fireforming involved.
The OP already has a 300 BO

11.5in Bison Recon BSP
"11.5” Recon profile BSP (Subsonic / full power) 6.8 SPC barrel with threaded muzzle for AR-15 platform rifles.
This barrel shoots both our 200 grain 6.8 BSP bullets at subsonic velocities and standard full-power factory 6.8 SPC loads flawlessly, easily cycling subsonic ammunition with a silencer. While the 16" BSP barrel will cycle 200 grain bullet subsonic ammo without a silencer, the 11.5" BSP barrel has too little dwell time to make this work. A silencer is needed for fully reliable cycling with the 11.5" BSP barrel when using subsonic ammunition."

6.8mm BSP Bullets
"The recommended load when using these bullets is: 14.0 to 14.5 grains Hodgdon H4895. OAL 2.260 inches. Their muzzle velocity is 1050 fps, and they will cycle the action of a 16" 6.8mm SPC rifle with carbine gas without further modification or a silencer. These bullets perform optimally with our 6.8 BSP Barrels"
16in Bison Recon BSP

So yes the 6.8 will do subsonic and super from the same barrel. As well as cycle with or without a suppressor if need be.
If I decided to switch so shooting subs with all the 6.8 stuff I have it would just be a barrel and then some projos to make it happen.

The next thing that will be said is the projos are not in stock, that is correct.
However they will be very soon.
As well they are other .277 heavier projos a guy could play with.
After all thats half the fun is it not.

Not to say having a 5.56 (which everyone should have first and keep IMHO) a 6.8 SPCII and then a .300 BO is a bad thing.
My personal preference is to have a 5.56 and a 6.8 first then add others as desired.
ymmv

2 barrels made differently then any other 6.8 barrel in order to get one projectile to function does not in anyway equal 99% of 300 blk barrels able to shoot numerous heavy gr subsonic bullets.  
I can easily give the 6.8spc all kinds of props.  subsonic is not one of them  And this 200gr woodleigh does not expand if I am reading correctly.  

Quoted from here: 6.8spc bison armory subsonic
Shooting 6.8mm Subsonic

The 1:7" twist of the 6.8 BSP barrel is just fast enough to stabilize our 200 grain bullets. At 100 yards, you will notice that the bullet holes in your target are somewhat oval, rather than round, which shows that the bullet is coning a small amount in flight. Since bullet expansion is typically poor at subsonic velocities, a slightly coning bullet is very effective, as it will produce a devastating injury.

So not only does it not expand but they are counting on tumbling for the wound effect. Which I have been told by countless individuals poo-pooing the 300blk sub, is not effective and a bad idea.   Ironically I actually agree and I don't count on tumbling and rely on properly designed bullets to expand at subsonic velocities. Now there are only 4 current 30 caliber heavy gr subsonic expanding bullets, but there are countless heavy gr 30 cal bullets that can be used for other purposes. Don't get me wrong I know for a a fact the kind of damage a tumbling bullet can do.  But I also know that I like the results from a bullet that expands even if just a little.  Because I have also found that if you have a subsonic that expands or opens up even just a little I can and do get consistent secondary effect of tumbling.

other then the 200gr 6.8 woodleigh there is how many heavy gr .277 bullets?  Midway usa list 2 bullets over 150 a 160  nosler and a 180 woodleigh.  so even if you can get the 180s to work subsonically, they are no better then plinkers and at $37 for 50 that makes them more then  twice the price of the .308 208gr amax which is one of the most popular subsonic loads for the 300blk

Also from their own page that same bullet they warn against shooting in anything but the 1/7 twist Bison Barrel.  where as that same concern does not cover 99% of 300blk barrels.  that means it is useless to a vast majority of 6.8spc shooters

Again I give 6.8spc all kinds of props 175 fps faster with the same bullet weight makes all the difference at 100 yds, which ironically is longer distance then 87% of guys shoot 87% of the time.

Alright, I see that, but was addressing that case prep in general,  is a one time thing.  After that, reloading any caliber becomes the same.

Size and trim.  Done.

btw- what's the going rate for once-fired, sized, trimmed 6.8spc brass per 1k?

I'm generally curious.

Also, does anyone have ballistics comparing a 110gr 6.8spc bullet fired from a ~8/8.5" barrel and a 110gr 300blk bullet fired from a ~8"/8.5" barrel?

Or 120gr/125gr....I'd just like to see what an apples to apples comparison (equivalent bullet weights and the shortest "standard" barrel length for these cartridges, ~8"/8.5") looks like in MV, KE and trajectory.

I have never looked for fully processed 6.8 brass.
I would rather get it once fired with spent primer intact.
I bump the shoulder back for my weapon not to saami specs.
Less wear and tear on the brass that way.

For a 300BO I get why you would want fully processed brass.

The 3500+ cases I have cost between .20 and .35 each depending on brand.
Although right now I would buy S&B loaded ammo for $11.99 at Palmetto before I bought brass.
The S&B is some of the best brass I have used and at .60 each its hard to justify not buying and firing factory ammo then reloading it.
.04 for a primer, .10 for powder, .18 for a projo thats .32 and I have to build it.
Figure S&B brass is worth .35 each and its cheaper to buy the loaded S&B and sell the brass or reload it.
You can litterally shoot the 6.8 with quality FMJ ammo for target or plinking for .25 each after you sell the brass.

BO is absolutely superior shooting subs, and it was designed with this purpose in mind as well as outperforming the basic combat load from 5.56 and 7.62x39 supers.

You have to understand why the 6.8 got away from fast twist barrels though. All of the fast twist barrels that may have been useful with heavier bullets had the wrong land / groove ratio, as well as the wrong chamber. Being that the 6.8 was primarily designed for supers and bullets in the 90gr-115gr range, once the chamber mistake was found and fixed ( back to the original, now spec II ), the determination was made that the proper twist rate for best velocity and accuracy with the correct groove ratio, was in the 1/11-1/12 range.

Once the round gained popularity, people started experimenting with, and wanting subs. BHW used the correct chamber and land/ groove ratio but with a faster twist to stabilize heavier subs. So far it isn't there IMHO from what I've seen. A heavy that is a tad shorter would probably work fine but there isn't one yet. Once there is, BO still wins subs because weight and frontal area matters, since velocity is limited.

Now, Gary, you've to stop with the 175fps faster stuff. Nobody makes or has made SAAMI chambers in years, and spec II ammo that 95% of all 6.8 shooters can use is much more than that.

I don't see a 6.5BRX offered at AR Performance, is this what they refer to as the six5?

I am a huge 6.8spc fan, I have no use for .223/5.56. I never gave the AR a second look until they became available in 6.8spc. As far as I'm concerned, it's the caliber the AR should've been introduced with in the beginning.
I bought a RRA LAR-6 and swapped out the stock heavy profile 16" 6-groove, 1:10 barrel with an ARP 16" Scout Profile 5-groove 1:11.25 melonite treated barrel, the weight savings was nice as was the increase in accuracy.
I later bought a DPMS A3 Lite in .223, not soon after I installed a Bison Armory 16" 6.8spc black stainless 4-groove 1:11 barrel, I sold the .223 ammo to buy more 6.8spc ammo, as I already had mags and > 2K rounds of ammo I didn't take too much of a loss.
I am fully vested in the 6.8spc and the more popular it becomes the better off we 6.8er's are.
I see no reason to go shorter or longer than 16", shorter requires extra fed involvement and cost and longer adds to the weight and not significantly more in performance.
But if you want an AR and you want to hunt with it, I see no reason why not to go the 6.8 route as you can find ammo available at most sporting goods stores and even better access on-line.
I have yet to hunt with it yet, but I have no reservations about taking on any medium to medium-large game, including bears, with it.

Pav I did not intentionally use a incorrect number.  I used the following, are these not the current loadings?  Which is above the SAAMI Spec chambers right? these are for the spec II chamber correct?

http://shopwilsoncombat.com/68-SPC-110-gr-Hornady-BTHP-2600-FPS-16-Barrel-20_Box/productinfo/A68-110-BTHP/

http://www.cheaperthandirt.com/product/8-HORN-8346

http://www.primaryarms.com/Hornady_6_8MM_SPC_110GR_V_MAX_20_200_p/h8346.htm

http://palmettostatearmory.com/index.php/sellier-bellot-6-8mm-rem-spc-110gr-fmj-20rds-sb68c.html

https://www.barrett.net/ammunition/68spc



I came up with an average of 2575 fps. Actually I got less then that, but rounded up.   I Don't yet reload for it so I based it off those.  I know for a fact that 110gr in the 300blk in a 16 inch barrel can get 2400fps.  there fore that gives 175fps faster.  if I used the wrong examples I apologize.  that was not my intent.  I did not remember the difference off the top of my head so I did a search before I posted that.

I will do this.  I will lower the 300blk to 2350 since that has been an oft repeated number.  and then give you the full 2600fps therefore giving a 250fps difference.  And then I will restate that at 100yds who cares?

All the factory ammo your quoting can be fired from the early 6.8SPC chamber (thank again Remington).

My 120SST's run 2575fps
110 Hornady BTHP 2700fps
95 TTSX 2900fps
130 VLD 2500fps
90gr Gold Dot 2825 to 2950 (2825 is .5 MOA, 2950 is .9 MOA)
16in barrel
The other big difference is bullets made for the 6.8 and the speeds it runs. (The VLD is not)
Not just what I listed but a bunch of them.

At 100 yards your right a 300BO will work just fine.
Beyond that the 6.8 runs away from it.
I mean come on its a shortened .223 case with a 30 cal projo, great for what it was built for.
Here in Montana a 300BO is great for HD but to short legged for hunting.

I have a friend that hunts Elk with a long barreled 454 Casull
Its good to 100 yards to

Halfway down the page
AR Perfornace
IN THE WORKS
The 6.5BRX in an AR15 is coming back.
The 6.5 fans have requested I bring back the 6.5BRX. It is apx 200fps faster than the 6.5 Grendel.
With the right bullet it can be one of the  flattest shooting AR15s made right behind the 6mmBRX.
6.5 Grendel bolts- improved design apx 24% stronger than ANY other Grendel bolt.-In Stock on bolt page

5.56x42- Based on the 6.8 case. The ultimate AR15 varmint cartridge, performance close to the 22-250
30 Herrett- based on the 6.8 case. The real semi-auto 30-30. 250 fps faster than the 300 AAC BLK

Six5
A BETTER MOUSE TRAP LWRC has developed a new lower receiver that uses Magpul pmags and allows loading to a 2.3" COAL. This has allowed us to design a chamber 41mm long based on the 6.8SPC. 6.8 bushing dies are used to neck down the case then the cases are trimmed to 1.620". That lets the popular long high BC 6.5 bullets like the 123gr Amax and SST, Barnes 100 and 120 TTSX, Nosler 120NBT and Lapua 100gr Scenar to be loaded to the cannelure or ogive without modifying mags like the 6.5x6.8 version requires. I believe our SIX5  design corrects all the problems with the wider PPC case used in the Grendel/264. The bolts are stronger, extractors are stronger and easier to find, Magpul mags feed better than any others. Hornady, Federal, SSA/Nosler and Remington makes brass. There is no need to hold the max pressure down to 52,000 PSI to keep bolts from breaking. The hoop stress around the chamber is less due to the cartridge being smaller diameter than the Grendel. In addition we use only 4150 11595E gunbarrel steel to increase the strength around the chamber over the weaker 416R stainless.  A normal AR15 lower receiver may be used, some steel mags like PRI allow loading to the same length as the Magpul mags. The performance will be apx the same as the Grendel/264.  Coming fall 2014

Mind posting a pic of your rig?

Actually at least as far as the Wilson stuff.  it does in fact say SPC II chamber only.  and it lists at 2600fps.

Does anyone have ballistics for an 8"/8.5" 6.8 barrel pushing 110gr/120gr/125gr bullets?

I'd really like to see how that particular barrel length and bullet weight compares to an 8"/8.5" 300blk pushing a 110gr/115gr/120gr/125gr bullets.

They just stopped the SPCII loads but didnt change the wording on their website.
The SPCII load ran 2850fps
This from the Wilson Combat Rep
"We had several customers with questionable guns (Spec 1, lower-end barrels, etc) have pressure issues with the original load. That and the inability to source appropriate powders consistently forced us to lower the pressure. "
Post #138

I cannot promise its accuracy.  I got it from a 6.8 guy who said he got it off the 6.8 forums

Well I don't Know what you want me to say.  I don't keep up with it enough to remember all the velocity claims. Screw it, you get better ballistics then a .308 winchester with the 2900fps non factory loads.  your right 300blk sucks.  

I have to use factory standards for 300blk.  the factory loads I have fired out of a 6.8  were nowhere near 2900fps with a 110gr bullet.  But 300 plus feet per second increase in velocity from original type one chambers, makes every thing else obsolete.  that is better then 6.5grendale hand loads.

Northtech Defense AR15 Billet Lower Reciever
Vltor MUR Upper reciever
Bison Armory Recon Barrel 6.8 SPCII Stainless
Geissele Super Dynamic Combat Trigger
Seekins Precision LoPro Adjustable Gas Block
Seekins Precision ATC Muzzle Brake
KNS Trigger Pins Gen2 Mod2 FDE
Magpul STR Stock Kit FDE
BCM H - Buffer
AR Performance 6.8 SPC Bolt 9310
Fail Zero Bolt Carrier
NIBx Cam Pin
DPMS Firing Pin
MI Gen 2 SS-Series 12in Rail FDE
Mil-spec Buffer Tube 7075
BCM Charging Handle Mod4
Magpul AFG2 Front Grip FDE
Magpul MBUS Rear Gen 2 FDE
Magpul MBUS Front Gen 2 FDE
Tapco End Plate Sling Adapter
Surefire M952 Weapon Light w/Cree 650 lumen led

The only thing I dont like is the scope mount, but its light and has not moved.
Oh and the Primary Arms 4x16x44 suprising glass for what it is, holds and returns to zero.

You have to go to a 20in barrel to get 2900 out of a 110, but the 2700 I get out of the 16in is not overly hot or hurting the brass.
I could push it harder but dont see the sense.
The BO does not suck, its great for what it was designed for.

My 12.5"

So whats your come up @ 400 yds.

About 1.75 mils or 6 MOA with the 110 at 2700 fps or 24in in kentucky talk lol.
The 120sst is about 2in higher aim point at 400

I shoot 90gr to 140 gr so it varies a bit.
The 130 vlds are right at 2 mils or 28in @ 400  


Nice weapon btw

Thanks, mine pretty standard aside from the Adams arms piston.  Are you a mil or moa guy?  hold or dial?

Depends on the situation
I practice both, I shoot usually 200 rounds or so at each range session.

thanks, I bought 10, and some of other 6.8 mags they had on sale.