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View Full Version : Thought on 6.8 spc in Ar-15 platform


Bwbraven
October 27, 2012, 10:28 PM
Is the 6.8 spc here to stay or will it fall to the way side with the 300 black out taking alot of interest lately. What's your thoughts? Would you buy a Ar or any rifle chambered in 6.8?

Metal god
October 28, 2012, 02:20 AM
IMO the 300 blackout is a crap round . At 120 grains it has good velocity at 2,100fps but terrible BC . At 220 grains it has good BC but terrible velocity 1,050fps . A 1911 can have that kind of ballistics with a 200+ gr bullet . I don't know the exact numbers but I would think the lighter blackout will stop traveling SS at about 500 yards or so and the 220gr bullet never getting there . Making 500yds it's max effective distance .

Thats just my thoughts on the blackout . Im sure there are some good uses for it . Maybe if you want a hard hitting CQC weapon the 300 blackout would work well . I could see it working well in urben areas where most of your shots are 100yds or less . The longest shot may be 2 to 300 yards tops .

The 6.8 has much better ballistics . It's bassically a 270 in a smaller case .It has a velocity of 2,400+fps and a range of 900yds or so .

I do plan to build a 6.8 AR but Im am torn between building the 6.8 or 223 wylde 20" bull barrel for my next build .

EDIT . My point is the 6.8 has much more potential and uses therefore I feel it will be around awhile .

Dan31
October 28, 2012, 02:32 AM
I thought I read recently that Hornady plans to ramp up production on ammo for it.

Marquezj16
October 28, 2012, 08:06 AM
Check out the 68 forum and you'll get the feeling that it has quite the support from the industry. DD, Wilson Combat, PSA, Stag Arms and more companies make barels or complete rifles. SSA, Hornady, SB, and Remington make ammo and you can reload. Also hearing the rumor that Federal will get in the mix with ammo and Wolf maybe next year.

dean1818
October 28, 2012, 10:36 AM
I had the same question..... I bought a 6.8 ar


Couldnt be happier

More vendors are coming on line.

6.8 Bullet performance is
Better at all ranges than the 300 blk.

As long as there are 270 rounds to reload, (up to 130 grain) there will be bullets for the 6.8.

6.8 has 80% of the 308 and is a great caliber for deer and hogs

I think you will be very happy with the 6.8

Bwbraven
October 28, 2012, 11:48 AM
I read in guns and ammo that more companies were doing the 6.5 Grendel but haven't seen anything along those lines of the 6.8.

bedlamite
October 28, 2012, 12:16 PM
I read in guns and ammo that more companies were doing the 6.5 Grendel

That's true since they became a SAAMI cartridge, but they still have a long way to catch up. One look at loaded ammunition at Midwayusa will give you an idea how far: they list (6) 6.5 Grendel loads, (30) 6.8SPC loads, and (18) 300 BO loads.

Also hearing the rumor that Federal will get in the mix with ammo]

Not a photoshop:

http://img.tapatalk.com/d/12/09/30/ybe7a3ar.jpg

Adamantium
October 28, 2012, 12:37 PM
If you plan on shooting distances greater than 150 yards, want a semi-auto to do it but don't want the projectile to be a 22 caliber bullet, 6.8 spc is a good choice. If any one of those three things don't apply than you would be better served by something else.

IMO the 300 blackout is a crap round .

When the bashing of other cartridges starts early you know it's a thread about the 6.8 spc. The inferiority complex that some 6.8 shooters have hurts my head...

bedlamite
October 28, 2012, 12:55 PM
300BO is crap? No.
Live up to the hype? Also no.

I had a 300 Whisper for a short time before I sold it and went 6.8. 300BO/300Whisper/300-221Fireball is good for a subsonic SBR with a suppressor, but it just doesn't have the velocity or BC to keep up with the either 6.8 or the 6.5.

spacecoast
October 28, 2012, 01:00 PM
The latest Shooting Times has a long article on the 6.5 Grendel which shows that the ballistics are superior to both the 5.56 and the 300 in the M4 platform, and slightly better than the 6.8. You might want to take a look before making a decision.

10-96
October 28, 2012, 01:02 PM
I have no regrets buying mine. I do wonder what's happened to the 90gr varmint loads of late- it's getting more rare that you can find any loads below 110gr. However, sonce I got into it- loads of 110gr and up have quadr... gone way the heck up.:D

bedlamite
October 28, 2012, 01:16 PM
The latest Shooting Times has a long article on the 6.5 Grendel which shows that the ballistics are superior to both the 5.56 and the 300 in the M4 platform, and slightly better than the worst 6.8 load available. You might want to take a look before making a decision.

FTFY. 6.5 Hunting bullets also don't have the high BC of the match bullets.

Bamashooter
October 28, 2012, 05:15 PM
I also dont care for the 300 blackout round. Its almost as pathetic as a 7.62x39 and nowhere near as good a caliber as the 7.62x51/.308. If I was looking for a hunting caliber for my AR it would either be a 6.5 grendel or 6.8spc. I think the 6.8 is all around better than the 5.56.

Palmetto-Pride
October 28, 2012, 08:21 PM
I like the 300 BLK for what it is a harder hitting mid range(300 yds or less) caliber for the AR-15 platform that only requires a barrel change to convert. I don't believe anyone is saying you could win 1000yd matches with it....:)

Adamantium
October 28, 2012, 11:04 PM
300BO is crap? No.
Live up to the hype? Also no.

What hype? It does exactly what it was advertised to do. If you are talking about people being enthusiastic about the caliber, that's the pot calling the kettle black. All these calibers are wimpy compared to ones that fit into a $300 short action bolt gun. That's just the nature of the game if you want to shoot it out of an AR15. A 300blk shoots a bigger caliber bullet and fits more rounds into a magazine so it's not a crime for it to have a lower muzzle velocity.

Jimro
October 28, 2012, 11:38 PM
6.8 is likely here to stay.

It is also likely to remain like the 10mm or 41 Magnum is to handgunners, kind of a niche loading, for people who like to hunt medium game in states where the minimum caliber is above 22.

The 6.5 Grendel is an interesting cartridge choice, but terminal ballistics aren't enough of a difference to separate it from heavy 223 loads, or 6.8 loads, and cost isn't low enough to tempt too many. It isn't exactly a true long range round (you run in to the same "run out of steam" issues as you do with anything put through the AR magwell,, just a tad further, but then you get into making your light handy rifle a big heavy monstrosity...)

Jimro

Theohazard
October 30, 2012, 10:26 AM
At 220 grains it has good BC but terrible velocity 1,050fps . A 1911 can have that kind of ballistics with a 200+ gr bullet
Not even close. The BC of the subsonic 300 BO round is far better than a handgun round, and therefore it shoots much, much flatter.

The 300 BO is a terrific round for its intended purpose: to allow a 5.56 AR to be easily switched to a .30 caliber bullet that can also work well with subsonic loads for suppressor use. The supersonic loads will duplicate the 7.62x39, and the subsonic loads allow you to be much quieter while supressed and yet still cycle the action. And the 300 BO subsonic rounds shoot much flatter than any subsonic handgun round.

jimbob86
October 30, 2012, 11:19 AM
The 6.8 has much better ballistics . It's bassically a 270 in a smaller case .It has a velocity of 2,400+fps and a range of 900yds or so .


If by that you mean "A 270 in a smaller case with 2/3 the muzzle velocity of the .270 WIN, and restricted to short, stumpy inefficient bullets, just in a smaller case" .... then, yeah, then "bassically" that's true ...... and "bassically", "a .30/30 is a .30-06 with 2/3 the velocity and restricted to inefficient round nosed or flat point bullets, just in a smaller case".....

900 yards?

A 110 gr .277 V-Max, assuming you could launch it @ 2400, would be subsonic past 600 ........ and would drop 46 FEET from a 100 yard zero by 900 yards ..... Wind drift would be measured in double digits as well .... energy would be down to .380 ACP levels ..... I you were trying to break windows in an apartment building, it'd do that pretty well ...... but so would .223.....

I like the 6.8, as a way to add lethality to the M-4 platform ..... but it is what it is, and it is not a "pocket .270". I think it'd be a great short range round for whitetail, if 130 gr bullets could be seated out long enough to launch at 2500 or so ..... but the 6.5G can do all that....

The 300 BLK is designed for suppressed SBR use.... I'd be all over that if that's what I needed done .....

Metal god
October 30, 2012, 01:33 PM
Not even close. The BC of the subsonic 300 BO round is far better than a handgun round, and therefore it shoots much, much flatter.

Yea I new I was going to catch some grief on that one .

If by that you mean "A 270 in a smaller case with 2/3 the muzzle velocity of the .270 WIN, and restricted to short, stumpy inefficient bullets, just in a smaller case"

Short answer yes all I meant by this is they shoot the same projectile

A 110 gr .277 V-Max, assuming you could launch it @ 2400, would be subsonic past 600 ........ and would drop 46 FEET from a 100 yard zero by 900 yards ..... Wind drift would be measured in double digits as well .... energy would be down to .380 ACP levels

I do not have the data on the 110gr v-max but that sounds about right do to it being a shorter lighter bullet with a BC of .370 .

However I was using the data on the 130gr sst with a BC of .460 . This bullet will shoot 900-ish yards . and yes both of these bullets have significant wind drift and bullet drop . Cus I don't have all the data on the 110gr v-max . I would guess the 130gr sst does a little better in both these areas .

bedlamite
October 30, 2012, 01:50 PM
A 110 gr .277 V-Max, assuming you could launch it @ 2400

You can launch a 110gr .277 Vmax at 2400fps, all you need is a 10" barrel. From a 16" barrel, it's much closer to 2700 fps.

tulsamal
October 30, 2012, 03:15 PM
I think it'd be a great short range round for whitetail, if 130 gr bullets could be seated out long enough to launch at 2500 or so ..

I've been reloading 6.8 for a couple of years now and I've never loaded a bullet heavier than 120 grains. There's just no need for that much bullet weight in that case. For deer or other big game, you just need to pick either a bonded bullet or a Barnes X bullet.

I like my 6.8 a lot. I have a wide variety of AR's but the 6.8 would be my choice if hunting was my main interest. A Barnes 85 or 95 grain bullet driven to max velocity in an SPC II chamber does amazing things to pigs and deer. I shoot a lot of 5.56mm and I've also reloaded it with the heavier bullets and used it for hunting deer from a stand. But the 6.8 takes your 5.56mm sized AR and bumps it up one level when it comes to the capability of the round. No one will argue that it is a 7.62 NATO round but the rifle is a lot smaller/lighter than an AR-10 as well.

Everybody should have an AR in 5.56mm. And then they should also have one in .22 LR. But for AR #3..... go 6.8!

Gregg

jimbob86
October 30, 2012, 10:05 PM
You can launch a 110gr .277 Vmax at 2400fps, all you need is a 10" barrel. From a 16" barrel, it's much closer to 2700 fps.

A 110 gr V-Max 6.8 SPC to 2700, from a carbine length gun? Really?

I'd like to see some hard data on that..... everything I have seen is maxing out around 24-2500 ....

And 130 gr loads are generally too long to fit in an AR magazine .... and take up too much case capacity, leaving too little room for propellant.... so velocity suffers.

How fast are you thinking you are launching a 130 SST there, Mg? Even if you launched it at full house 270 WIN velocity (3100!), it'd still drop 17 feet from a 100 yard zero, and have nearly 6 feet of wind drift in a 10mph crosswind..... but you'll never get that much velocity out of the 6.8, in any barrel length ...... it's not effective at 900 .....


To stay supersonic at that distance, you need more efficient bullets than are generally available in the .277 bore ..... Berger makes a .277 VLD with a .531 G1 BC ..... but that weighs 150 gr .... good luck gettting even 30/30 belocity out of that in the 6.8 ......

Metal god
October 30, 2012, 11:43 PM
Check these out . Looks like getting the velocity up with the 6.8 is no problem . My guess is none of these loads are maxed out do to liability concerns .

http://www.targetsportsusa.com/p-3344-hornady-custom-68mm-remington-spc-120-grain-sst-ammunition.aspx

And this one , holy cow :eek: http://www.targetsportsusa.com/p-1179-remington-premier-match-ammunition-68mm-remington-spc-115-grain-sierra-matchking-hollow-point-box-of-20.aspx

http://www.hornady.com/store/6.8mm-SPC-110-gr-V-MAX/

http://www.hornady.com/store/6.8mm-SPC-120-GR-SST/

I'm in no way saying that the 6.8 is a great 1,000 yard round . Just that it has more versatility and potential then the 300 blackout in the ways I would most likely use them . I was making the point to the OP . IMO the 6.8 is more virsatile then the 300 .So I believe it will be around and used more by the general public .

bedlamite
October 31, 2012, 06:45 AM
A 110 gr V-Max 6.8 SPC to 2700, from a carbine length gun? Really?

http://shopwilsoncombat.com/68-SPC/products/409/

There also seems to be a myth that longer barrels are useless in the 6.8, here's what it's capable of with a 24" barrel. (http://68forums.com/forums/showthread.php?29229-AA-2200-in-24in-BHW-barreled-AR-%28Todays-Test%29)

hodaka
October 31, 2012, 06:54 AM
I have begun to find once fired 6.8 brass, discarded at the range. I think that it is here to stay. Just bought an 18" Stag upper to add to my 16" carbine.

Marquezj16
October 31, 2012, 07:04 AM
I need to go to your range and get some brass. :D

jimbob86
October 31, 2012, 07:23 AM
bed- I'm curious what pressure those AA2200 loads in your link are working at ...and what level of safety margin they have..... I could run 3200 f/sec .270 WIN loads with 48.5 gr of IMR 4064 .... but that'd wreck cases on a mild day, and guns on a hot one.

The Hornady 120gr SST load almost has enough energy to be a 300 yard deer round .... near perfect fo kids! With a longer barrel ...... maybe on my list.

With the small case capacity, it'd be conducive to using a suppressor, too .... another plus for it. I know it's still supersonic, but I want the can to dampen muzzle blast to make the gun more user friendly, not to make it silent.

The 6.5G was looking really good to me for this, but since I already stock .277 bullets......

The only downside for my purposes is that .277 and .264 suppressors are pretty much a build your own proposition...... a can made for the .308 would work, just not as well.


It's an interesting round, and I may very well get one*..... but there's still no way it is has an effective range of 900 yards......

*Probably a bolt action with a long throat .....

Bwbraven
October 31, 2012, 08:25 AM
A wealth of info and opinions thanks guys. Both cartridges were designed to add umph to a small platform and for that I agree both are great rounds but from a hunting perspective where most shots are going to be 500 yards or less the 6.8 is a flatter shooting more accurate round. I don't want to have to start doping just past 100yards is basically what I'm saying.

Eppie
October 31, 2012, 08:27 AM
The origin of the 6.8 was the military and there it hangs in the balance. It is an experimental caliber. If the military adopts it will trive, if it doesn't it will likely slowly wither.

There!!! fixed it. But I do like a good laugh:p

jimbob86
October 31, 2012, 09:29 AM
The origin of the 6.8 was the military and there it hangs in the balance. It is an experimentary caliber.

I think I have misunderestimated the malleability of the American language.... :D

I doubt it will go away if hunters find it usefull. With the popularity of the AR rifle, and the unsuitability of the .223 round out of carbine length AR's for deer hunting, I see a niche there.....

120 grains at 2450 with a BC of .4 beats the tar outa a thuddy-thuddy for bambi applications..... and a 6.8 upper will cost less han a new levergun, too.

bedlamite
October 31, 2012, 04:41 PM
jimbob- WRT pressure, you need to know that there are two levels of loads out there, similar to the difference between .223 Remington and 5.56 NATO:

Remington screwed up the cone angle and leade on the print they submitted to SAAMI. AFAIK, only Ruger and Model 1 Sales still use this chamber, but there are still some out there from other companies several years ago, that is the source of the neutered loads that you commonly read about, and most factory ammo is still loaded to work in the SAAMI chamber, including the 120 grains at 2450 load you mentioned.

Most use the spc2 chamber, and that along with a 3-5 groove 1:11-1:12 twist barrel will make all the difference in the velocity you can achieve. Technically, it's not the number of grooves or twist that makes the difference, it's the bore area, and the 6 groove 1:10 barrels were intended for 270 Winchester and have a smaller bore area, the 3-5 groove and slower twist was developed specifically for the 6.8. The proper combination can reduce chamber pressure by over 10K psi, allowing more powder and higher velocity. Handloading is where this cartridge really shines, you could easily get over 2500fps with that same 120gr SST from a 16" barrel and IMO it's too heavy for this cartridge, best efficiency is from 90-110gr. I prefer the 110gr Nosler Accubond for Hunting.

This load was Speer 90gr TNT on 29.4gr of H4198 at 2930 fps from my 16" spc2 5R 1-11.25 barrel. Yes, that is 2 full grains above the max SAAMI load that Hodgdon lists from a 24" test barrel. This brass has been loaded several times already, note the lack of ejector swipes and the primers are round where the firing pin hit:

http://i328.photobucket.com/albums/l342/1k_wayne/guns/primers.jpg

jimbob86
October 31, 2012, 05:00 PM
Primers seem to have plenty of radius left .... I am intrigued.....

stubbicatt
November 1, 2012, 09:41 AM
Not specific to the 6.8, but in general, the firearms industry creates the need they seek to satisfy, not unlike an old Baptist preacher...

Every year they (collectively) roll out some new chambering, which everybody has to go out and buy, so then they create ammunition for that chambering, accessories for that firearm, and then, next cycle, repeat.

In the next cycle, all the stuff that was de rigeur in the last cycle finds its way to the unused pile.

Lather, rinse, repeat.

As I see it, the cartridges most likely to remain are those which are, or were, military chamberings, as they will do most jobs adequately, if not excellently, and components are always available. Whether the 6.8 fits in this category remains to be seen. As I understand it, the .mil has had a lukewarm reaction to oddball cartridges, perhaps due to deficiencies in the supply system.

There are exceptions of course, like the 243 and 270, but even these are probably not as popular as they were 30+ years ago, what with the advent of the "new" WSSM or similar chamberings.

YMMV.

EdInk
November 1, 2012, 09:51 AM
A buddy of mine has one for deer hunting and loves it. My thoughts are the 6.8 is a good round that has alot of potential for hunting and LE use. The widespread availablity of 5.56 will keep it from becoming the top AR round but it will IMHO outlast most of the other newer AR rounds.

Eppie
November 1, 2012, 11:21 AM
I hope the military will get behind the 6.8 catridge and move away from the .223

A couple of years ago I was talking to my son-in-law, who has done two tours of Iraq, and I was showing him my POF 308. He said that he would have loved to have it while in Iraq.

It happened to him that several times, while on patrol, the enemy would pop-up from behind mud walls, the .223 rounds would not penetrate but the AKs rounds (7.62x39) did. After that they assigned M-14s to two squad members.

The 223 was really for jungle fighting not desert fighting. As always our beloved government is way behind the ball.

http://thefiringline.com/forums/attachment.php?attachmentid=84576&stc=1&d=1351786957

Jimro
November 3, 2012, 10:10 AM
Eppie,

Not likely to happen. The .mil just invested a bunch of money in "barrier blind" ammunition to punch through things like automotive windshields. The Army has M855A1, the USMC Mk318.

Those two M14's were for the Squad Designated Marksmen, who have the job of supporting the squad with precision fires as part of their Rifleman duties.

I don't see that many folks outside of SOCOM using the 6.8, and even then a lot of SOCOM guys are choosing the SOPMOD M4 with 77gr Mk262 Mod1 ammo.

Jimro

Eppie
November 3, 2012, 11:39 AM
Yesterday I received my Guns & Ammo issue and one of the articles supports your conclusion.

There is just too much inertia and in the system. We're buying $20 million aircraft that have no opposing air force, but sending out troops with M-4 and M14.